Four companies submitted the quotations for building a bridge, with the following values of breaking stress `(B_(s))` and working stress `(W_(s))` expressed in `N//m^(2)`
(A) `B_(s) = 25 xx 10^(8), W_(s) = 15 xx 10^(8)`
(B) `B_(s) = 20 xx 10^(8), W_(s) = 15 xx 10^(8)`
(C ) `B_(s) = 25 xx 10^(8), W_(s) = 12.5 xx 10^(8)`
(D) `B_(s) = 25 xx 10^(8), W_(s) = 20 xx 10^(8)`
To whome the contract should be given, if all of them have quoted the same amount ?

Options

A. B
B. D
C. C
D. A

Answer

B

Explanation

The calculations for the factor of safety (f) for A, B, C, D are as follows :
(A) `f_(1) = (B_(s))/(W_(s)) = (25 xx 10^(8))/(15 xx 10^(8)) = (5)/(3)`
(B) `f_(2) = (20 xx 10^(8))/(15 xx 10^(8)) = (4)/(3)`
(C ) `f_(3) = (25 xx 10^(8))/(12.5 xx 10^(8)) = 2`
(D) `f_(4) = (25 xx 10^(8))/(20 xx 10^(8)) = (5)/(4)`
Contract should be given to (C ) as the company is keeping the maximum safety.