Mary’s annual income is $15,000 and John’s annual income is $18,000. By how much must Mary’s annual income increase so that it constitutes 60% of Mary and John’s combined income? Choose the correct choice from the following choices.
A) $3,000 B) $4,000 C) $7,000 D) $12,000 E) $25,000
Let Mary's income increase by x, then the equation will be   15,000 + x= (60/100)* (15,000 + x + 18000 )   15,000 + x = (3/5) * (33,000 + x)   75,000 + 5x = 3x + 99,000   2x = 24,000   x = 12,000   So, Answer will be $12,000
<result>D</result>
Mary’s annual income is $15,000 and John’s annual income is $18,000. By how much must Mary’s annual income increase so that it constitutes 60% of Mary and John’s combined income?