Mark has $6.35 in quarters and dimes. he has 5 more than twice as many dimes as quarters. how many quarters does mark have?

Mark has 12 quarters

Step-by-step explanation:

I did all of it, nickles, dimes, and of course, quarters..

So, Let +n+ = the number of nickels he has

Let +d+ = the number of dimes he has

Let +q+ = the number of quarters he has

given:

(1) +q+=+2n+

(2) +d+=+n+%2B+3+

(3) +5n+%2B+10d+%2B+25q+=+420+

( the units for this equation is cents , for instance,

$4.20 is 420 cents

All you have to do is substitute (1) and (2) into (3)

so that the only variable is +n+, then solve

(3) +5n+%2B+10%2A%28+n+%2B+3+%29+%2B+25%2A%282n%29+=+420+

(3) +5n+%2B+10n+%2B+30+%2B+50n+=+420+

(3) +65n+%2B+30+=+420+

Subtract +30+ from both sides

(3) +65n+=+390+

(3) +n+=+6+

And since

(2) +d+=+n+%2B+3+

(2) +d+=+6+%2B+3+

(2) +d+=+9+

Also, since

(1) +q+=+2n+

(1) +q+=+2%2A6+

(1) +q+=+12+

: Mark has 6 nickels, 9 dimes, and 12 quarters

Adam

Step-by-step explanation:

You just have to divide feet/second

Adam: 15 feet per second

15/1=15

Noah runs 599 feet in 40 seconds

599/40=14.9

Jake runs 1 mile in 384 seconds

1 mile=5280 feet

5280/384=13.8

liz runs 667 feet in 1 minute

1 minute=60 seconds

667/60=11.1