Question 1164747

Robert is thinking that his father is 7 years older than twice his age, his grandfather is 4 years less than twice his father’s age. If Robert’s grandfather is 70 years old, how old is Robert?
<pre>Let Richard's age be R
Then his father's is: 2R + 7, and his grandfather's is: 2(2R + 7) - 4
We then get: 2(2R + 7) - 4 = 70
4R + 14 - 4 = 70
4R = 60
Richard or {{{highlight_green(matrix(1,6, R, "=", 60/4, "=", 15, years-old))}}}