Lana collects 20-cent and 50-cent coins. The total value of her coins is currently $9.70. If Lana has 4 more 50-cent coins than 20-cent coins, how many of each type does she have?
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Lana collects 20-cent and 50-cent coins. The total value of her coins is currently $9.70. If Lana has 4 more 50-cent coins than 20-cent coins, how many of each type does she have?
Let F stand for the number of 50¢ coins
Let T stand for the number of 20¢ coins
50F + 20T = 970 (equation 1)
F = T + 4 (equation 2)
substitute (T+4) in place of F in eq 1
50(T+4) + 20T = 970
50T + 200 + 20T = 970
70T = 770
T = 11
F = T + 4
F = 15
check answer
50F + 20T = 970
(50)(15) + (20)(11) =? 970
750 + 220 =? 970
970 = 970 true
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