The number 79825x42y3 is divisible by 99. What is the geometric mean x and y?
- 2
- 3
- 2√2
- 2√3
Sol:
(24+y) – ( 16 + x ) → divisible by 11
(8 + y – x)
⇒ y – x = 3 or -8
(40 + x + y) → divisible by 9
⇒ x + y = 5 or 14
Taking y – x = 3 and x + y = 5
Y = 4 and x = 1
⇒ Geometric mean =√xy=2
