Answer:
Step-by-step explanation:So we know x + y = 21 and 5x +10y = 165 We line them up in columns x + y = 21 5x +10y = 165 To eliminate the x variable, I'll multiply every element in the 1st equation by -5. -5x + -5y = -105 5x + 10y = 165 Now we combine (add) the equations, which eliminates x altogether. 5y = 60 ... y = 12 From there, x + 12 = 21 ... x = 21-12 ... x = 9 You should double check. Do 9 nickles and 12 dimes equal $1.65? A very important thing to remember using this method is to do the same thing to each element in the equation that you change! I hope that helps.
Answer:
15/13
Step-by-step explanation:
Answer:
small=15 large=40
Step-by-step explanation:
x=large box
y=small box
55 = x + y
50x + 55y = 2825
50x + 55( 55 - x) = 2825
50x + 3025 - 55x = 2825
0 = 55x - 50 x + 2825 - 3025
0 = 5x - 200
200 = 5x
x=40
y = 15
Answer:
Present age
Son: 15
Father: 45
Step-by-step explanation:
Remark
Thank you for the translation. Without it, the problem would be impossible -- at least for me.
Givens
Let the present age of the father = x
Let the present age of the son = y
Solution
x + y = 60
How many years will pass? You could say it's z.
x + z = y When z years pass, the son will be his father's present age.
x + z + y + z = 120 when z is added to both their current ages, the result is 120 Collect like terms
x + y + 2z = 120
<u>x + y = 60 </u> Subtract The very first equation
2z = 60 Divide by 2
z = 60/2 30 years have passed.
z = 30
x + z = y
x + 30 = y Substitute x + 30 for the present y value (the father).
x + x + 30 = 60
2x = 30
x = 15
x + y = 60
15 + y = 60
y = 60 - 15
y = 45
So the son's age right now is 15
The father's age right now is 45
Answer:
6 pizzas
Step-by-step explanation:
7 people × 7 slices each
= 49 slices in total
If each pizza has 9 slices
to get 49 slices ....we divide 49 by 9 to get 5.4
And in order to get a whole we must make it 6 pizzas because 5 is not enough and 6 is more than enough