The diameter of a small gear is 16 cm. This is 2.5 cm more than 1/4 of the diameter of a larger gear. What is the diameter of the larger gear ?

Question

What is the answer I am confused

Answer 1

let d = diameter of the larger gear.

Here's what we know:

16 = d / 4 + 2.5 (the smaller gear (16) is 2.5 cm more than a fourth of the larger gear)

 

So we need to isolate d. We start by subtracting 2.5:

16 - 2.5 = d / 4 + 2.5 - 2.5

13.5 = d / 4

Now we multiply by 4:

13.5 * 4 = d / 4 * 4

54 = d

 

So the larger gear's diameter is 54 cm long.