SSC CGL Number Series Quiz 1

Solution: The correct answer is 39.

Explanation: The given series is 8, 15, 26, ?, 56, 75. Let’s analyze the pattern:

$$
\begin{array}{cccccc}
8 & 15 & 26 & 39 & 56 & 75 \\
\downarrow & \downarrow & \downarrow & \downarrow & \downarrow \\
+7 & +11 & +13 & +17 & +19 \\
\downarrow & \downarrow & \downarrow & \downarrow \\
+4 & +2 & +4 & +2 \\
\end{array}
$$

The pattern shows that each number is derived by adding a progressively changing difference. The differences between the consecutive numbers are +7, +11, +13, +17, +19, and the changes between these differences follow the pattern +4, +2, +4, +2. Therefore, the missing number in the sequence is **39**.

Solution: The correct answer is 155.

Explanation: The given series is 33, 80, 108, ?, 183, 230, 258. Let’s analyze the pattern using differences:

\[
\begin{array}{ccccccc}
33 & \rightarrow & 80 & \rightarrow & 108 & \rightarrow & ? \\
& +47 & & +28 & & +47 & \\
\end{array}
\]

The pattern alternates between adding 47 and 28:

\[
\begin{align*}
33 + 47 &= 80 \\
80 + 28 &= 108 \\
108 + 47 &= 155 \quad \text{(missing number)} \\
155 + 28 &= 183
\end{align*}
\]

Continuing this pattern, the missing number in the sequence is **155**.

Solution: The correct answer is 19.

Explanation: The given series is 15, ?, 27, 39, 55, 75. Let’s analyze the pattern using differences:

\[
\begin{array}{cccccc}
15 & \rightarrow & ? & \rightarrow & 27 & \rightarrow & 39 & \rightarrow & 55 & \rightarrow & 75 \\
& +? & & +8 & & +12 & & +16 & & +20 \\
\end{array}
\]

The pattern involves increasing differences: +8, +12, +16, +20. If we go backward from 27, we subtract 8:

\[
\begin{align*}
27 – 8 &= 19 \quad \text{(missing number)}
\end{align*}
\]

Therefore, the missing number in the sequence is **19**.

Solution: The correct answer is 35.

Explanation: The given series is 19, 26, ?, 46, 59, 74. Let’s analyze the pattern using differences:

\[
\begin{array}{cccccc}
19 & \rightarrow & 26 & \rightarrow & ? & \rightarrow & 46 & \rightarrow & 59 & \rightarrow & 74 \\
& +7 & & +9 & & +11 & & +13 & & +15 \\
\end{array}
\]

The pattern involves increasing differences by 2 each time: +7, +9, +11, +13, +15. Following this pattern:

\[
\begin{align*}
26 + 9 &= 35 \quad \text{(missing number)}
\end{align*}
\]

Therefore, the missing number in the sequence is **35**.

Solution: The correct answer is 488.

Explanation: The given series is 512, 508, 500, 496, ?, 484. Let’s analyze the pattern using differences:

\[
\begin{array}{cccccc}
512 & \rightarrow & 508 & \rightarrow & 500 & \rightarrow & 496 & \rightarrow & ? & \rightarrow & 484 \\
& -4 & & -8 & & -4 & & -8 & & -4 \\
\end{array}
\]

The pattern alternates between subtracting 4 and subtracting 8. Following this pattern:

\[
\begin{align*}
496 – 8 &= 488 \quad \text{(missing number)}
\end{align*}
\]

Therefore, the missing number in the sequence is **488**.

Solution: The correct answer is 56.

Explanation: The given series is 43, 52, 47, ?, 51, 60, 55. Let’s analyze the pattern using differences:

\[
\begin{array}{ccccccc}
43 & \rightarrow & 52 & \rightarrow & 47 & \rightarrow & ? & \rightarrow & 51 & \rightarrow & 60 & \rightarrow & 55 \\
& +9 & & -5 & & +9 & & -5 & & +9 & & -5 \\
\end{array}
\]

The pattern alternates between adding 9 and subtracting 5. Following this pattern:

\[
\begin{align*}
47 + 9 &= 56 \quad \text{(missing number)}
\end{align*}
\]

Therefore, the missing number in the sequence is **56**.

Solution: The correct answer is 25.

Explanation: The given series is 80, 73, 64, 53, 40, ?. Let’s analyze the pattern using differences:

\[
\begin{array}{cccccc}
80 & \rightarrow & 73 & \rightarrow & 64 & \rightarrow & 53 & \rightarrow & 40 & \rightarrow & ? \\
& -7 & & -9 & & -11 & & -13 & & -15 \\
\end{array}
\]

The pattern involves subtracting consecutive odd numbers. Continuing this pattern:

\[
\begin{align*}
40 – 15 &= 25 \quad \text{(missing number)}
\end{align*}
\]

Therefore, the missing number in the sequence is **25**.

Solution: The correct answer is 68.

Explanation: The given series is 82, 79, 71, ?, 60, 57, 49. Let’s analyze the pattern using differences:

\[
\begin{array}{ccccccc}
82 & \rightarrow & 79 & \rightarrow & 71 & \rightarrow & ? & \rightarrow & 60 & \rightarrow & 57 & \rightarrow & 49 \\
& -3 & & -8 & & -3 & & -8 & & -3 \\
\end{array}
\]

The pattern alternates between subtracting 3 and 8. Following this pattern:

\[
\begin{align*}
71 – 3 &= 68 \quad \text{(missing number)}
\end{align*}
\]

Therefore, the missing number in the sequence is **68**.

Solution: The correct answer is 190.

Explanation: The given series is 325, 271, 226, ?, 163, 145, 136. Let’s analyze the pattern using differences:

\[
\begin{array}{cccccc}
325 & \rightarrow & 271 & \rightarrow & 226 & \rightarrow & ? & \rightarrow & 163 & \rightarrow & 145 & \rightarrow & 136 \\
& -54 & & -45 & & -36 & & -27 & & -18 & & -9 \\
\end{array}
\]

The pattern involves decreasing differences by 9 each time. Continuing this pattern:

\[
\begin{align*}
226 – 36 &= 190 \quad \text{(missing number)}
\end{align*}
\]

Therefore, the missing number in the sequence is **190**.

Solution: The correct answer is 75.

Explanation: The given series is 108, 99, 88, ?, 60, 43. Let’s analyze the pattern using differences:

\[
\begin{array}{cccccc}
108 & \rightarrow & 99 & \rightarrow & 88 & \rightarrow & ? & \rightarrow & 60 & \rightarrow & 43 \\
& -9 & & -11 & & -13 & & -15 & & -17 \\
\end{array}
\]

The pattern involves subtracting consecutive odd numbers. Continuing this pattern:

\[
\begin{align*}
88 – 13 &= 75 \quad \text{(missing number)}
\end{align*}
\]

Therefore, the missing number in the sequence is **75**.