A plumber has 150m of pipes. The plumber uses 20% fitting a central heating system, and then 25% of what is left to fit a bathroom. How much pipe does the plumber use to fit the bathroom?

30 m

Step-by-step explanation:

Total length of pipe = 150 m

Central heating system = 20% of 150 m

= 0.2 × 150

= 30 m

Length of pipe remaining = 150 m - 30 m

= 120 m

Bathroom fitting = 25% of 120 m

= 0.25 × 120

= 30 m

The plumber used 30 m of pipe to fit the bathroom

the amount you'd have after the work is $1.55

step-by-step explanation:

you subtract 95% from $31.