back to math video class
Example of word problem solving
Question:
Tom earns 10% more than Kevin and Kevin earns 3/5 of what John earns. What percent of John's earning is Tom's?
Solution:
translate the words into mathematics expression
Let T be Tom's earning and K be Karen's earning
Tom earns 10% more than Kevin
T = K + (10/100)K = K(1 + 10/100) = K(1 + 1/10) = (11/10)K
Kevin earns 3/5 of what John earns
K = (3/5)J
both side of the equation multiply 5
5K = 3J
express J in terms of K
J = (5/3)K
What percent of John's earning is Tom's?
T/J = [(11/10)K]/[(5/3)K] = (11/10)K ÷ (5/3)K = (11/10)K × (3/5K) = (11 × 3)/(10 × 5) = 33/50 = 66/100
so T = (66/100)J
Tom's earning is 66/100 of John's earning.