SOLUTION: adele went to the post office to buy stamps and postcards. she bought a total of 25 stamps some 39 cent stamps and the rest 23 cent postcards. if she paid $8.47 altogether, how man
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-> SOLUTION: adele went to the post office to buy stamps and postcards. she bought a total of 25 stamps some 39 cent stamps and the rest 23 cent postcards. if she paid $8.47 altogether, how man
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Question 222057: adele went to the post office to buy stamps and postcards. she bought a total of 25 stamps some 39 cent stamps and the rest 23 cent postcards. if she paid $8.47 altogether, how many 39 cent stamps did she buy? Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! she bought a total of 25 stamps some 39 cent stamps and the rest 23 cent postcards.
if she paid $8.47 altogether, how many 39 cent stamps did she buy?
:
Let s = no. of 39 cent stamps
and
Let p = no. of 23 cent stamps
;
write an equation for each statement:
:
"she bought a total of 25 stamps some 39 cent stamps and the rest 23 cent"
s + p = 25
arrange for use as substitution
p = (25-s)
:
"if she paid $8.47 altogether," let's just deal in cents
39s + 23p = 847
:
Replace p with (25-s) in the above equation, find s
39s + 23(25-s) = 847
39s + 575 - 23s = 847
39s - 23s = 847 - 575
16s = 272
s =
s = 17 ea 39 cent stamps
and
25 - 17 = 8 ea 23 cent stamps
;
;
Is this true?
.39(17) + .23(8) =
6.63 + 1.84 = 8.47, seems to be
