So, the first thing you want to find out is how many seconds each person adds to the wait time. Find out how many seconds are in 20 minutes.. 20*60=120. 120/150=0.8 seconds. Each person adds 0.8 seconds to the wait time. Now, multiply that by 240.. 240*0.8=192 seconds. Lastly, find out how many minutes 192 seconds is... 192/60=32 minutes.
I hope I did that right! And if I did, I hope that helped!

5 0

3 years ago

Whats 1/5 - 1/7 please can you tell me how to work it out<br> thanks

Andrej [43]

Convert the fractions so they both have the same denominator (bottom part of the fraction)

1/5 = 7/35

This is because 5*7=35, so 1*7=7

1/7 = 5/35

This is because 7*5=35, so 1*5 =5

Then subtract the top numbers to get the answer:

$\frac{7}{35}-\frac{5}{35} = \frac{2}{35}$

3 0

3 years ago

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