A is twice as good a workman as B and they took 7 days together to do the work B alone can do it in.
Choose one.
A) 22 B) 77 C) 21 D) 77 E) 88
W21 = 2:1   2x + x = 1/7   x = 1/21 =&gt; 21 days   Answer: 21
<result>C</result>
A is twice as good a workman as B and they took 7 days together to do the work B alone can do it in.