general Maths Puzzle

Three boys A,B and C were asked to work out 180 problems. A could do 9 out of 10 correctly,B 13 out of 15 correctly and C 5 out of 6 correctly. What is the least number that that were done right by all the three ?

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Three boys A,B and C were asked to work out 180 problems. A could do 9 out of 10 correctly,B 13 out of 15 correctly and C 5 out of 6 correctly.

A did 162 correct and 18 wrong.
B did 24 wrong.
C did 30 wrong.

If all wrong were done by individuals separately, then
max wrong by someone = 18+24+30 = 72
the least number that that were done right by all the three = 180-72=108
12 years agoHelpfull: Yes(3) No(2)

180-(18+24+30)=108 is the answer.
out of 180,A could do 170 correctly,B could do 156 correctly,C could do 150 correctly.UNDER THE CONDITION THAT the least number OF QUESTIONS were done right by all the three, WE CONCLUDE THERE IS NO INTERSECTION BETWEEN THE WRONG ANSWERS MADE BY 3
12 years agoHelpfull: Yes(3) No(2)

general Other Question

A man walks 2 km. in first hour and then two thirds of this distance in second hour and then two thirds of the distance covered in the previous hour in the third hour.. and so on. What is the maximum distance walked ? If 50% of (x-y)=30% of (x+y), then what percent of x is y ?