Question
For what number of values of 'z' is the number 1269zq
divisible by 15?Solution
ATQ,
Divisible by 15 ⇒ divisible by 5 and 3
Divisible by 5 ⇒ q = 0 or 5
Divisible by 3 ⇒ sum divisible by 3
Case 1: q = 0
Sum = 1 + 2 + 6 + 9 + z + 0 = z + 18
Divisible by 3 ⇒ z = 0, 3, 6, 9
Case 2: q = 5
Sum = 1 + 2 + 6 + 9 + z + 5 = z + 23
Divisible by 3 ⇒ z = 1, 4, 7
Total values of z: 4 + 3 = 7
3Â Â Â Â Â Â Â Â Â 6Â Â Â Â Â Â Â Â Â 18Â Â Â Â Â 149Â Â Â Â Â Â Â Â 602Â Â Â Â Â Â Â Â 15057
...1, 1, 3, 15, 105, 942
- Find the wrong number in the given number series.
8, 14, 24, 49, 59, 84 2, 4, 16, 48, 240, 1440, 10080
1001, 934, 863, 790, 711, 630, 539
Find the wrong number in the given number series.
1728, 121, 1000, 729, 512, 49
Find the wrong number in the given number series.
21, 31, 11, 41, 1, 61Find the wrong number in the given number series.
548, 532, 568, 510, 604, 460
9Â Â Â Â Â Â Â Â Â Â Â Â Â 17Â Â Â Â Â Â Â Â Â Â 53Â Â Â Â Â Â Â Â Â Â 103Â Â Â Â Â Â Â Â 310Â Â Â Â Â Â Â Â 619
...43, 42, 41, 39, 33, 10
