#Mathematics; 3+5=35 PUZZLE; Reasoning problems with solution;Can you solve this?

Problem Solving s5

A student can solve 2 out of 4 problems of mathematics, 3 out of 5 problem of physics, and 4 out of 5 problems of chemistry. There are equal number of books of math, physics, and chemistry in his shelf. He selects one book randomly and attempts 10 problems from it. If he solves the first problem, then the probability that he will be able to solve the second problem is 2/3 b. 25/38 c. 13/21 d. 14/23

Problem Solving on Liquid Solutions

Given the probability that A can solve a problem is 2/3, and the probability that B can solve the same problem is 3/5, find the probability that (i) at least one of A and B will solve the problem (ii) None of the two will solve the problem.

Given the probability that A can solve a problem is 2/3 and the probability that B can solve the same problem is 3/5. Find the probability that none of the two will be able to solve the problem.