Question

To stitch a shirt, 2m 15 cm cloth is needed. To find the number of shirts that can be stitched from a 40m cloth and the amount of cloth will remain?

Answer 1

Hint: To solve the problem, we first convert all the numerical parameters into the same unit. In this case, we will convert everything into cm. Thus,
2m 15cm = $2\times 100+15$= 215 cm (Since, 1m = 100cm)
40m = $40\times 100$= 4000 cm

Complete step-by-step answer:
Finally, to get the number of shirts, we divide the total amount of cloth available from the amount of cloth needed to make a shirt. The quotient will give us the number of shirts and the remainder gives us the amount of cloth remaining.
Now, while solving this question, we assume that there is no wastage of cloth. For example, if suppose, we cut cloth into certain portions, we would not be left with any wastage. (that is entire cloth is utilized for our purpose)
In this question, we have 4000 cm of cloth. Now a shirt requires 215 cm of cloth. Thus, to solve this question, we use the unitary method. To explain this method-
Say, 1 bag cost 50 rupees, then from 1 rupee would be equivalent to $\dfrac{1}{50}$ of the bag. Similarly, in this question, we have,
1 shirt requires 215 cm cloth.
Thus from 1 cm of cloth, it is equivalent to $\dfrac{1}{215}$shirt.
Since, we have 4000 cm cloth, this would be equivalent to $\dfrac{4000}{215}$ shirts
Now, the amount of cloth that remains (that is the amount of cloth which is incapable to make a shirt) will be given by the remainder of $\dfrac{4000}{215}$. Further, the quotient would give the number of entire shirts that could be made.
We get, quotient = 18 and remainder = 130
Thus, we could make 18 shirts and have 130 cm of cloth remaining.

Note: It is important to realize that one would get the same answer even if the units were converted into metres. In this case,
2m 15cm = $2+\dfrac{15}{100}=2.15$m. Since, 1cm = $\dfrac{1}{100}$m
Thus, in this case, to get a number of shirts, we divide 2.15 by 40. So, we get,
$\dfrac{40}{2.15}=\dfrac{40}{2.15}\times \dfrac{100}{100}=\dfrac{4000}{215}$shirts
We could now see that quotient is 18 and remainder is 130, which would result in the same answer. Thus, one can solve the question in any units of length.