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A does 20% less work than B. If A can complete a piece of work in $${\text{7}}\frac{1}{2}$$ hours, then B can do it in ?
Answer & Solution
Correct Answer:
Option
C
Ratio of times taken by A and B
$$\eqalign{ & = 100:80 \cr & = 5:4 \cr} $$
Suppose B takes x hours to do the work
$$\eqalign{ & \Rightarrow 5:4::\frac{{15}}{2}:x \cr & \Rightarrow x = \left( {\frac{{4 \times 15}}{{2 \times 5}}} \right) \cr & \Rightarrow x = 6{\text{ hours}}{\text{}} \cr} $$
$$\eqalign{ & = 100:80 \cr & = 5:4 \cr} $$
Suppose B takes x hours to do the work
$$\eqalign{ & \Rightarrow 5:4::\frac{{15}}{2}:x \cr & \Rightarrow x = \left( {\frac{{4 \times 15}}{{2 \times 5}}} \right) \cr & \Rightarrow x = 6{\text{ hours}}{\text{}} \cr} $$
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