Answer:
605 boys
Step-by-step explanation:
If the ratio of boys to girls is 5:7
and there are 847 girls
we can plug this value into the ratio by doing something like:
5:7
= 5/7
= x/847
Because the ratio has to be the same, we can substitute x for the number of boys and solve by the cross method or whatever you guys call it.
5 x
--- x ------
7 847
The x in the middle is just to show the direction you are multiplying.
the 5 is multiplied by the 847 and the 7 is multiplied by x.
847 * 5 = 4,235
4,235 divided by 7 is 605
605 is your answer.
The cross method can be used in most situations.
* is used to represent multiplication btw
Answer:
135
Step-by-step explanation:
43 times 3 is 135
Y + x = 5x + 3
12 - y = x + 2y
Isolate x in the first equation, then substitute its expression into the second equation to find y:
y + x = 5x + 3
x = 5x - y + 3
-4x = -y + 3
x = y - 3/4
---
12 - y = x + 2y
12 - y = (y - 3/4) + 2y
48 - 4y = y - 3 + 8y
48 - 4y = 9y - 3
-4y = 9y -51
-13y = -51
y = 51/13
Substitute this into the first equation to find x:
51/13 + x = 5x + 3
x - 5x = 3 - 51/13
-4x = -12/13
x = 3/13
Lastly, substitute back into both original equations to check work;
y + x = 5x + 3 --> 51/13 + 3/13 = 5(3/13) + 3 --> 54/13 = 54/13
12 - y = x + 2y --> 12 - 51/13 = 3/13 + 2(51/13) --> 105/13 = 105/13
Answer:
x = 3/13
y = 51/13
Hope this helps.
Answer: The answer is 9
Step-by-step explanation: -2(6 - r) + 6
-12+2r=6
+12 +12
2r= 18
2 2
r= 9
