Answer:
34.78 is the answer to ur question
So r+c=42
c=4+r
subsitute c=4+r for r in r+c=42
r+4+r=42
add like terms
2r+4=42
subtract 4 from both sides
2r=38
divide both sides by 2
r=19
rob=19
subsitute r=19 for r in c=4+r
c=19+4
carly=23
Answer:
$15.75
Step-by-step explanation:

y × 100 = 5 × 15
100y = 75
100y ÷ 100 = 75 ÷ 100
y = 0.75
$15 - $0.75
$14.25

y × 100 = 10 × 15
100y = 150
100y ÷ 100 = 150 ÷ 100
y = 1.5
$14.25 + $1.50
$15.75
I turn the mixed numbers into decimals before doing anything else.
11 2/5----> 57/5----> 11.4
4 2/7----> 30/7----> 4.29
2 1/7----> 15/7----> 2.14
11.4=q-4.29+2.14
11.4=q-2.15
13.55= q
13.55 converted to a fraction is 13 11⁄20
q=13 11⁄20