Answer:
The number of points won by the first child was 37 points
The number of points won by the second child was 119 points
The number of points won by the third child was 624 points
Explanation:
The question in English is
In a computer game, three children won together 780 points. The second child gained 3 times more points than the first and 8 more points, the third child gained four times more points than the first two in one place. How many points did each child earn
Let
x ----> number of points won by the first child
y ----> number of points won by the second child
z ----> number of points won by the third child
we know that
three children won together 780 points
so
----> equation A
The second child gained 3 times more points than the first and 8 more points
----> equation B
the third child gained four times more points than the first two in one place
----> equation C
Solve the system by substitution
step 1
substitute equation B in equation C
![z=4(x+3x+8)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/zh180q6pbw85do1ksl97gh0lz90zbfg0w9.png)
----> equation D
step 2
substitute equation D and equation B in equation A
![x+(3x+8)+(16x+32)=780](https://img.qammunity.org/2021/formulas/mathematics/middle-school/48h41ttojd8nr34ahvecxpacw9p27w20je.png)
step 3
solve for x
![20x+40=780\\20x=740\\x=37](https://img.qammunity.org/2021/formulas/mathematics/middle-school/3yt9gy6ko3spsbt5hfzjl2tevwwc3hk1yl.png)
step 4
Find the value of y
![y=3(37)+8=119](https://img.qammunity.org/2021/formulas/mathematics/middle-school/mxwj2lnl7n4fh8nnucmvae6zdtr5ehg4zt.png)
step 5
Find the value of z
![z=16(37)+32=624](https://img.qammunity.org/2021/formulas/mathematics/middle-school/cxvudozqtyvidmkr3tu0kzyk5l3hl4wmiz.png)
therefore
The number of points won by the first child was 37 points
The number of points won by the second child was 119 points
The number of points won by the third child was 624 points