If 1≤x≤3 and 3≤y≤5. The least possible average of 1/x and 1/y is: (A) 2/3 (B) 3/5 (C) 4/15 (D) 8/15 (E) 4 /5

(C) 4/15

Step-by-step explanation:

Given that 1 ≤ x ≤ 3 and we need to find the least value of 1/x. The least value of 1/x is gotten by taking the maximum value of x in the interval, hence the least value of 1/x = 1/5

Given that 3 ≤ y ≤ 5 and we need to find the least value of 1/y. The least value of 1/y is gotten by taking the maximum value of y in the interval, hence the least value of 1/y = 1/3

The least possible average of 1/x and 1/y =

example 2 – simplify: step 1: completely factor both the numerators and denominators of all fractions. step 2: change the division sign to a multiplication sign and flip (or reciprocate) the fraction after the division sign; essential you need to multiply by the reciprocal. step 3 : cancel or reduce the fractions.