book Maths Puzzle Numerical Ability

the answer to the following should be 4/3a, however, I cannot understand how - please help! Thank you!!

1/1.5 + 1/1.5=

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book Other Question

2 = 10 + z
------ (Suppose to mean 10 plus z divided by -3.)
-3
twice a number divided by 5 is that number subtracted from 14