Active maths 4

UhmMaths?!

Stuck on another question set guys:

Q.17 page 65
Working together, Peter and Simon can build a wall in four hours. It would take peter 15 hours more than Simon . How long would it take Peter and Simon to build the wall if working alone?

I chose Simon to be x
And Peter to be x+15
And then I was stuck.

Q.20 page 65
Two taps running together take 6 minutes to fill a bath. The hot tap, working by itself, takes 100 seconds longer to fill the bath than the cold tap working by itself. To the nearest second, how long would it take each tap to fill the bath by itself?

I let cold tap= x
And I got confused if hot tap is equal to x+1.4 or something else(because it's 100 seconds)

Help would be much appreciated

Yakuza

You need to think in terms of work rates.
Take a look here:
http://www.algebra.com/algebra/homework/Rate-of-work-word-problems/HOW-TO-Solve-Rate-of-Work-Problems.lesson