SOLUTION: : A man bought 15 books for
#9800. Some of these books cost #600 each
and the rest cost #700 each. How many of
each type did he buy.
Algebra ->
Finance
-> SOLUTION: : A man bought 15 books for
#9800. Some of these books cost #600 each
and the rest cost #700 each. How many of
each type did he buy.
Log On
Question 1198001: : A man bought 15 books for
#9800. Some of these books cost #600 each
and the rest cost #700 each. How many of
each type did he buy. Found 3 solutions by Alan3354, ikleyn, josgarithmetic:Answer by Alan3354(69443) (Show Source):
You can put this solution on YOUR website! : A man bought 15 books for
#9800. Some of these books cost #600 each
and the rest cost #700 each. How many of
each type did he buy.
------------------
x + y = 15
600x + 700y = 9800
You can put this solution on YOUR website! .
A man bought 15 books for #9800.
Some of these books cost #600 each and the rest cost #700 each.
How many of each type did he buy.
~~~~~~~~~~~~~~~~~~
If all 15 books cost #600 each, the total would be 15*600 = 9000.
Comparing it with #9800, we conclude that 8 books cost #700 each,
while the rest 15-8 = 7 books cost #600 each.
ANSWER. 7 books at #600 each and 8 books at 700 each.
CHECK. 7*600 + 8*700 = 4200 + 5600 = 9800, which is precisely correct.
Solved mentally, without using equation/equations, by mental reasoning, only.
(