C is the answer to the problem
Is 1500 ml greater than less than or equal to 1.5 l is equal.
1.a3,b3 and c3 must be 2 digit number.
2. a3 must be greater than all the other number.
examples: a3-b3-c3=93-83-73
a3-b3-c3=43-33-23
Let x be the time required to do the job when they work together.
1/x = 1/9 + 1/10 = 19/90
x = 90/19 = 4.7 hours
