| Question | Select the number from among the given options that can replace the question mark (?) in the following series. 10, 22, 42, 86, 170, 340, ? | |
| Type | multiple_choice | |
| Option | 743 | incorrect |
| Option | 631 | incorrect |
| Option | 634 | incorrect |
| Option | 678 | correct |
| Solution | 10 × 2 + 2 = 22 22 × 2 – 2 = 42 42 × 2 + 2 = 86 86 × 2 – 2 = 170 170 × 2 + 2 = 340 340 × 2 – 2 = 678 10, 22, 42, 86, 170, 340, 678. | |
