Question

plzzz answer 17 and 19

Answer 1

1 hour work of 3 taps is 1/3
tap A is 1/10
tap B is 1/15
let tap C is 1/x

so tap A + B + C = 1/3
1/x = 1/3-1/6
1/x=1/6
so x= 6 hours


let fix charge be x and additional be y

so x+60y=960
x+80y=1260
eliminate x
-20y=-300
y=15

put y=15 in equation 1
x+900=960
so x=60