Question 1187555

Tom had 4/5 as many stamps as Michael. After Michael gave away 3/7 of his stamps, Tom had 40 more stamps than Michael. How many stamps did Tom have?
<pre>Let number Tom had, be T
Then Michael had: {{{5T/4}}}
If Michael gave away {{{3/7}}}, then he had: {{{matrix(1,3, (4/7)(5T/4), "=", 5T/7)}}} remaining 
We then get: {{{matrix(1,3, 5T/7, "=", T - 40)}}}
              5T = 7T - 280 ------ Multiplying by LCD, 7
         5T - 7T = - 280
            - 2T = - 280
Original number Tom had. or {{{highlight_green(matrix(1,5, T, "=", (- 280)/(- 2), "=", 140))}}}