Question

A business executive bought 40 stamps for $14.40 the purchase included 39cent stamps and 24cent stamps how many of each type of stamps how many of each type of stamps were bought show 3 steps identify the veritable set up an equation and solve and write a conclusion

Answer 1

hello

let's allow x represent the number of 39 cent stamp

let's allow y represent the numbers of 24 cent stamp

40 = x + y .... equation 1

this equation represents the total number of stamos

14.40 = 0.39x + 0.24y ....equation 2

this equation represents the summation cost of each type of stamp

we can proceed to solve these set of equations

from equation 1

40 = x + y

let's make x the subject of formula

`\begin{gathered} 40=x+y \\ x=40-y \end{gathered}`

x = 40 - y .....equation 3

now we csn substitute equation 3 into equation 2 and solve

`\begin{gathered} 14.40=0.39x+0.24y \\ x=40-y \\ 14.40=0.39(40-y)+0.24y \\ 14.40=\mleft\lbrace(0.39*40)-(0.39* y)\mright\rbrace+0.24y \\ 14.40=15.6-0.39y+0.24y \\ 14.40=15.6-0.15y \\ 0.15y=15.6-14.40 \\ 0.15y=1.2 \\ y=(1.2)/(0.15) \\ y=8 \end{gathered}`

y = 8

put y = 8 in either equation 1 or 2

from equation 1

`\begin{gathered} 40=x+y \\ y=8 \\ 40=x+8 \\ x=40-8 \\ x=32 \end{gathered}`