A man bought 42 stamps, some 13¢ and some 18¢. How many of each kind did he buy if the cost was $6.66? If x represents the number of 13 cent stamps and y the 18 cent stamps, which system represents the problem? x + y = 42 and 0.13x + 0.18y = 6.66 x + y = 6.66 and 0.13x = 0.18y 0.13x + 0.18y = 42 and x + y = 6.66

24 $.18 stamps (y)= $4.32
18 $.13 stamps (x)= $2.34
______
$6.66
x + y = 42 18 + 24 = 42 (stamps)
.0.13x + .0.18y= 6.66 $ 0.13 (18) +$ 0.18 (24) = $6.66

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parmesanchilliwack parmesanchilliwack · Answer 2 · 2018-11-16T08:43:52+01:00

Answer: He bought 18 and 24 stamps of 13 cent and 18 cent respectively and equations 0.13x + 0.18y = 6.66, x+y=42 represent the problem.

Explanation:

Since according to the question man bought total 42 stamps in which some are of 13 cent while some are of 12 cent. And, x represents the number of 13 cent and y represents the number of 18 cent.

So, we can write, x+y=42 ---------(1)

Again, according to the question 13x cent+18y cent= 6.66 $ -------(2)

Since, 1$= 100 Cent, so we can write 13x cent=0.13x $, and 18y cent= 0.18 $

So, from equation (2) , 0.13x +0.18y=6.66 ----------(3)

on applying substitution method in equation (1) and (3).

We get, x=18 stamps and y=24 stamps.