Answer:
- Jan 2018: 7.83 million
- Feb 2017: 8.12 million
Explanation:
Your "Grandma formula" tells you ...
N = G(1 +x/100)
Solving for G gives ...
G = N/(1 +x/100) . . . . . . G = old value; N = new value; x = % change
For this problem, N=7.9 million.
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1) x = 0.9, so G = 7.9/(1 +.9/100) ≈ 7.83 . . . million
7.83 million people were looking for work in January 2018.
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2) x = -2.7, so G = 7.9/(1 -2.7/100) ≈ 8.12 . . . million
8.12 million people were looking for work in February 2017.