Using proportions, it is found that Ms. Grant had $18,896 of his total savings left after making the donation.
What is a proportion?
A proportion is a fraction of a total amount, and the measures are related using a rule of three.
In this problem, she saved $80 a month for 22 years = 22 x 12 months, hence the total amount saved is given by:
T = 80 x 22 x 12 = $21,120.
She donated 20% of her savings to a charity, hence she retained 80% of the total amount, which is given by:
R = 0.8 x 21,120 = $18,896.
More can be learned about proportions at https://brainly.com/question/24372153
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