Question

Machine A and Machine B are each used to make 660 widgets. It takes Machine A x hours longer to produce 660 widgets than Machine B. Machine B produces y % more widgets per hour than Machine A. How long does it take Machine A to make 660 widgets?

Answer 1

A. x + 100x/y

Explanation:

Machine A= x hours longer to produce 660 widget than machine B

Machine B produces y% more widget per hour than machine A

let

b = Number of hours it takes Machine B to make 660 widgets.

Time taken for Machine A to make the 660 widgets = x + b.

Rate of Machine B = 660/b

Rate of Machine A = 660 / (x + b).

Machine B produces y% more widgets per hour than Machine A:

660 / (x + b)(1 + y/100) = 660/b

1 / (x + b)(1 + y/100) = 1 / b

Multiply both sides by (x+b)

1 + y/100 = (x + b)/b

1 + y/100 = x/b + 1

Subtract 1 from both sides

y/100 = x/b

Take the inverse of both sides

100/y = b/x

Make b the subject

100x/y = b

b=100x/y

The time taken for Machine A to make the 660 widgets is x + b = x + 100x/y.

Answer is A. x + 100x/y