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Lili24
Phil has 11 stamps of denominations $0.37 and $0.23. If the total value of the stamps is $3.23 how many $0.37 stamps does Phil have?
let phil has x number of stamps of $0.37 denomination then he will be having (11-x) number of stamps of @0.23 denomination in this case \[{{0.37}\times{x}}+{{0.23}\times(11-x)} = 3.23\] now solve this equation
\[{0.37x}-{0.23x}= 3.23 - 0.23\times11\] \[0.14x = 3.23 - 2.53\] \[0.14x = 0.7\] \[x= {{0.7}\over{0.14}}=5\]