Question

When open together,inlets a and b can fill an empty tank in 7 hours approximately.If inlet a alone can fill the empty tank in 15 hours approximately.What time will inlet b take to completly fill the empty tank?

Answer 1

let x be the speed of water flowing through tank

$1 \div x \: \: + 1 \div x \times 15 \: \: = 15$