Question 969658
p = number of 1 peso coins
n = number of 5 peso coins
d = number of 10 peso coins


p = n
p + n + d = 20
p + 5n + 10d = 88


2n + d = 20
6n + 10d = 88


20n + 10d = 200
-(6n + 10d = 88)
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14n = 112
n = 8


--> 8 1-peso coins, 8 5-peso coins, 4 10-peso coins.