The price of raw materials has gone up by 15%, labor cost has also increased from 25% of the cost of raw material to 30% of the cost of raw material. By how much percentage should there be reduction in the usage of raw materials so as to keep the cost same?
A. 28%
B. 17%
C. 27%
D. 24%
E. Cannot determined
Answer: Option B
Solution (By Examveda Team)
Let the initial cost of raw material be 100. So, initial labor cost was 25 and net cost was 125 Now, 15% increment in raw materials cost and labor cost has gone up to 30% from 25 % Raw material cost = 115 And Labor cost = (115 × 30%) = 34.5 So, New net cost, = 115 + 34.5 = 149.5 Difference of labor cost = 149.5 - 125 = 24.5 % reduction = $$\frac{{24.5 \times 100}}{{149.5}}$$ = 17%(approx.)This Question Belongs to Arithmetic Ability >> Percentage
let, raw material 100 then 15% up it is now 115
30% increase in the labor cost of raw material so 30% of 115 is = 34.5
when the cost was 25% raw material was priced at 100 so 25% of 100 is = 25
now, the total increase when it became 30% is 115+34.5 = 149.5
previously 25% so the total was = 125
the difference = 149.5 - 125 = 24.5
now, % = (24.5*100)/149.5 = 16.388 ~ 17%(appx.)
24.5 kaha se aaya????