Time And Work Ques 37
Question-
What is the ratio between the hours taken to complete work 1 and 2 separately, if all the labours work together on work 1 and 2 separately?
(1) $10: 17$
(2) $9: 14$
(3) $7: 11$
(4) $8: 15$
(5) $6: 11$
Show Answer
Correct Answer: (3)
Solution: (3)
All labours complete work 1
in $=1 \div\left(\frac{1}{3}+\frac{1}{2}+\frac{1}{5}+\frac{1}{8}+\frac{1}{4}\right)$ $=1 \div \frac{169}{120}=\frac{120}{169}=0.7$
Hours taken $=10 \times 0.7$ $=7$ hours
All labours complete work 2 in $=1 \div\left(\frac{1}{5}+\frac{1}{5}+\frac{1}{8}+\frac{1}{4}+\frac{1}{10}\right)$ $=1 \div\left(\frac{8+8+5+10+4}{40}\right)$ $=1 \div \frac{35}{40}=\frac{40}{35}=\frac{8}{7}=1.1$
Hours taken $=1.1 \times 10$ $=11$ hours
Required ratio $=7: 11$
BETA
