Overlap Strip question

[Angel Haroon]

How to do this question? I have tried the unitary method but the answer is wrong.

 

[lev888]

How to do this question? I have tried the unitary method but the answer is wrong.

Please post your solution.

 

[Angel Haroon]

10cm overlap = 50cm long strip
xcm = 56cm

x=560/50
x= 1.12cm

and this is the wrong answer.

 

[Cubist]

It might help if you think about this:-

If the overlap is reduced by 1cm then how long would the double strip be? (so the overlap becomes 9cm)

 

[Dr.Peterson]

10cm overlap = 50cm long strip
xcm = 56cm

x=560/50
x= 1.12cm

and this is the wrong answer.

You're assuming this is proportional; it isn't, because it's about addition and subtraction, not multiplication.

If I were you, I might think about how long each strip is; solving that would teach you what you need to reverse the process and answer the question. Observe that the amount of overlap is subtracted from the sum.

 

[HallsofIvy]

Call the length of each strip x. Overlapping the second strip by 10 cm adds x- 10 to the length. We have x+ x- 10= 50 so 2x= 60. Each strip has length x= 30 cm.

Let the overlap for the next two strips be y. Then the length will be 30+ (30- y)= 60-y= 56. Solve that for y.