Question

Sarah had 189 more stamps than her sister. After their mother gave her 75 stamps and her sister 46 stamps, Sarah had twice as many stamps as her sister. How.many stamps did Sarah have at first?

Answer 1

Sar = 189 + s

Sar + 75 = 2 (s + 46) = 2 s + 92
so
s + 189 + 75 = 2 s + 92
s = 172
so
Sar = 189 + 172 = 361
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Check
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189 + 172 = 361
361 + 75 = 436
436/2 = 218
and 172 +46 = 218 sure enough