11 Plus Exams Forum

Wooden strips 10cm wide are used to cover a floor 4m long and 3.5m wide. Find the total length of the strips.

The answer is 140m.

I can't see how to get to that answer. Can anyone help. Thanks

So you would need 35 strips to cover the width (3.5m / 10cm)
4m long x 35 = 140m

Thanks. Ok I am being really dense. I had got to the 35 strips but why does multiplying the length of the floor give you the total length of the strips? We have drawn it out but can't see it.

140m would be the length of all the strips laid end to end.

Imagine your wooden strip came on a 10cm wide roll. You would cutoff a 4m length of it to cover the the floor from one end to the other. Then lay another 4m strip alongside that one. And repeat that (35 times altogether) until the whole floor was covered. You would end up with 35 4m x 10cm strips. Which on the original roll had you not cut it off in sections would have been 140m.

Of course adding all the lengths of the 35 strips together
Thank you.

If your child sketched this out the thinking should flow quite clearly.