Findx:
xþy¼ 5000
xþ 1800 ¼ 5000
xþ 1800 1800 ¼ 5000 1800
x¼$ 3200
Hence, he has $3200 invested at 4% and $1800 invested at 6^12 %.
EVALUATION: Check the second equation.
4 %xþ 6
1
2
%y¼ 245
0 : 04 ð 3200 Þþ 0 : 065 ð 1800 Þ¼ 245
128 þ 117 ¼ 245
245 ¼ 245
Try These
Use two equations with two unknowns.
- One number is 4 times another number. If their sum is 40, find the
numbers. - The sum of the digits of a two-digit number is 14. If the digits are
reversed, the new number is 18 more than the original number. Find
the number. - A person has 18 coins, some of which are nickels and the rest of which
are dimes. If the total amount of the coins is $1.30, find the number of
nickels and dimes. - Matt is 4 times older than Mike. In 10 years, he will be twice as old as
Mike. Find their ages.
220 LESSON 18 Using Two Equations