If he spent 3/7 of his money on souvenirs, it means that he had kept 4/7 of his money...
4/7 M = 16
7 4/7 M = 16 7
4M = 112
M = 112/4
Therefore:
M = 28
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Answer:
Joshua had $28 to begin with but spent $12 of his money.
We can check if this is the correct result by multiplying $28 by 3/7.
3/7 * $28
= ($28*3)/7
= ($84)/7
= $12