tess has 100 dimes and quarters, if the total of the coins is $21.40 how many of each of the coins does she have? Using substitution or elimination find the answer

Answer: 24 and 76

Step-by-step explanation:

{

d

+

q

=

100

10

d

+

25

q

=

2140

From the first equation, we have

d

=

100

-

q

Substituting that into the second equation, we have

10

(

100

-

q

)

+

25

q

=

2140

⇒

1000

-

10

q

+

25

q

=

2140

⇒

15

q

=

1140

⇒

q

=

1140

15

=

76

Knowing that

q

=

76

we can substitute that value into the first equation to obtain

d

+

76

=

100

∴

d

=

24

Thus, Sue has

24

dimes and

76

quarters.