Let's call the 13¢ stamps a and the 18¢ stamps b:
a+b = 42 and therefore a= 42-b (formula 1)
0.13a+0.18b= 6.66 In this formula, substitute the value of a according to formula 1:
0.13(42-b)+0.18b= 6.66 Multiply on the left to get rid of the parenthesis:
5.46-0.13b+0.18b= 6.66 Subtract 5.46 from both sides:
-0.13b+0.18b= 1.20 Add on the left:
0.05b= 1.20 Divide both sides by 0.05
b= 24 You have 24 18¢ stamps and:
42-24= 18 13¢ stamps
Check: (24 x 0.18) + (18 x 0.13)= 6.66 Correct.
The numbers are "x" and "y";
Therefore, we can suggest this system of equations:
x+y=24 ⇒x=24-y
x/y=5
solve this problem by substitution method.
(24-y)/y=5
24-y=5y
-y-5y=-24
-6y=-24
y=-24/-6=4
x=24-y
x=24-4
x=20
Answer: the numer are: 20 and 4
Answer:
100 gallons
Step-by-step explanation:
so 1 gallon equals 4quarts multiply that by 25 you get 100 so there you go
