5x + y = 15
y = -5x + 15
Substituting y= -5x+15 from first equation into second equation:
3x + 2y = 16
3x + 2·(-5x + 15) = 16
3x - 10x + 30 = 16
-7x + 30 = 16
7x = 30 - 16 = 14
x = 2
Substituting x=2 into the first equation:
5x + y = 15
5(2) + y = 15
10 + y = 15
y = 15 - 10
y = 5
So your final answers are x=2 and y=5.
Let x be the 1st number
x + 9 be the second number
Equation:
x + x+9 = 171
Solution:
2x + 9 = 171
2x = 171 - 9
2x = 162
x = 81
x + 9 = 90
81 + 90 = 171
Answer:
Total amount Silas and Raja has at first = $252
Step-by-step explanation:
Let,
Amount Silas had = x
Amount Raja had = y
According to given statement;
x = 3y Eqn 1
x-84 = y+42 Eqn 2
Putting value of x from Eqn 1 in Eqn 2
3y - 84 = y+42
3y-y = 42+84
2y = 126
Dividing both sides by 2

Putting y = 63 in Eqn 1
x = 63(3)
x = 189
Total amount they had = 189 + 63 = $252
Hence,
Total amount Silas and Raja has at first = $252
Answer:
Mark up = 33.33%
Step-by-step explanation:
Given that:
buying price = $75
selling price = $100
First we will find the difference between two prices:
Difference = 100 - 75 = $25
We will find now that 25 is what percent of 75 so:
=25/75* 100
= 0.333333 * 100
= 33.33%
So the store marked the price by 33.33% instead of 30%
i hope it will help you!