Saved Bookmarks
| 1. |
Let d + 2(2b + c) = 19. What will be the remainder when the 4-digit number abcd is divided by 8?1. 22. 53. 04. 3 |
|
Answer» Correct Answer - Option 4 : 3 Given: d + 2(2b + c) = 19 Concept used : Divisibility rule of 8 A number is divisible by 8 if last 3 digits are divisible by 8 Calculations : abcd = 1000a + 100b + 10c + d For abcd to be divisible by 8, 100b + 10c + d must be divisible by 8 (100b + 10c + d)/8 = [100b + 10c + 19 - 2(2b + c)]/8 [d = 19 - 2(2b + c)] ⇒ (100b + 10c - 4b - 2c + 19)/8 ⇒ (96b + 8c + 19)/8 ⇒ (96b + 8c)/8) + 19/8 We can see that 96b + 8c is divisible by 8 and only 19 will give remainder Remainder = 3 ∴ Remainder will be 3 when abcd is divided by 8 |
|