You were right, its the second choice CA=CB+BA
Answer:
84
Step-by-step explanation:
x = number of girls
The total for boys is 2x * 81 and for girls it would be 90x
Therefore, the equation goes like this:
2x * 81 + 90x
Then simplify, and set to equal 3x...
3x = 252
Which is the same as
x = 84
Thank me later :)

so, as you can see above, the common ratio r = 1/2, now, what term is +4 anyway?


so is the 8th term, then, let's find the Sum of the first 8 terms.

![\bf S_8=512\left[ \cfrac{1-\left( \frac{1}{2} \right)^8}{1-\frac{1}{2}} \right]\implies S_8=512\left(\cfrac{1-\frac{1}{256}}{\frac{1}{2}} \right)\implies S_8=512\left(\cfrac{\frac{255}{256}}{\frac{1}{2}} \right)\\\\\\S_8=512\cdot \cfrac{255}{128}\implies S_8=1020](https://tex.z-dn.net/?f=%20%5Cbf%20S_8%3D512%5Cleft%5B%20%5Ccfrac%7B1-%5Cleft%28%20%5Cfrac%7B1%7D%7B2%7D%20%5Cright%29%5E8%7D%7B1-%5Cfrac%7B1%7D%7B2%7D%7D%20%5Cright%5D%5Cimplies%20S_8%3D512%5Cleft%28%5Ccfrac%7B1-%5Cfrac%7B1%7D%7B256%7D%7D%7B%5Cfrac%7B1%7D%7B2%7D%7D%20%20%5Cright%29%5Cimplies%20S_8%3D512%5Cleft%28%5Ccfrac%7B%5Cfrac%7B255%7D%7B256%7D%7D%7B%5Cfrac%7B1%7D%7B2%7D%7D%20%20%5Cright%29%5C%5C%5C%5C%5C%5CS_8%3D512%5Ccdot%20%5Ccfrac%7B255%7D%7B128%7D%5Cimplies%20S_8%3D1020%20)
Answer:
Es 2.6
Step-by-step explanation: