Answer is A. From1 we know the sum of tens digits of B and C is equal to tens digit of A. What this means is that there is carry over from the sum of tenses digit of B and C. You can pick a few examples to see that the Sum of hundreds digit of B and C will be equal to the hundreds digit of A. So thi...

Since question is asking for an approximate answer something close to the rel answer is good enough.

2+5 + 2root(10)
Let's take the two cases you can check.
1. 2 + 5 + 2 root(9) = 13
2. 2 + 5 + 2 root(16) = 15

You know that root(10) is closer to root(9) than root(16)
hence 13 is the answer.

The subject of the sentence has to be Neanderthals (plural) because of using 1. and so were (Neanderthals were) probabaly without language 2. Why they (Neanderthals) were supplanted A. Usage of those is wrong because Vocal tract is singular B. Correct comparison because the resembled an ape's (posse...

The argument does not talk about who generally donates to the charities. It indicates that wealthy people don't get any deductions and hence they probably might stop contributing to charities. Therefore we can not assume that only wealthy people donate to charities. Also if D is true then A also has...

The conclusion of the argument is that the corporations should use the titles externally and not internally. The first statement does not support the conclusion i.e. it states the executives should complete shun using titles. The second statement supports the final conclusion of the argument and thi...

Can you post the entire question?

The equation is |X-9/2| = 5/2
When you solve this the two cases are X-9/2 > 0 and X-9/2 <0
You assumed X > 0 and X <0 which are not the right equations.
Both cases give you two solutions for X.

Is the question asking how many solutions exist for X?

I really don't see anything wrong with A. 'shaped' is modifying the noun wings and seems the adverbs smoothly and perfectly are parallel and they refer to the verb shaped. B. has issue with parallelism and also there is no need to repeat wings again C. You don't need to use 'that' because the second...

5^21 x 4^11 = 2 x 10^n solve for n

answer is n=21, I'm not sure how to get there.

5^21 x 4^11= 5^21 x (2^2)^11= 5^21 x 2^22

2 x 10^n = 2 x (5x2)^n=2 x 5^n x 2^n=5^n x 2^n+1

Therefore 5^21 x 2^22 = 5^n x 2^n+1
You can see n = 21