Retired Moderator
Joined: 07 Jun 2014
Posts: 4813
Given Kudos: 0
WE:Business Development (Energy and Utilities)
Re: If Nash had 12 grandchildren and three times as many grand
[#permalink]
27 May 2018, 12:37
Explanation
Rather than assigning separate variables to the granddaughters and grandsons, define them both in terms of the same unknown multiplier, based on the ratio given:
Number of granddaughters = 3m
Number of grandsons = m
Note that you are solving for 3m, not for m!
3m + m = 12
4m = 12
m = 3
3m = 9
Alternatively, suppose that Nash had exactly one grandson and three granddaughters.
That would sum to four grandchildren altogether. Triple the number of grandsons and granddaughters to triple the number of grandchildren.