1st statement
Justin has 7.5 more than Eva 7.5+E
Eva = E
2nd statement
Emma has 12 less than Justin J - 12
when J= Justin = 7.5 + E
last statement
Eva+Justin+Emma = 63
E + (7.5+E) + (7.5+E-12) =63
ADD UP
3E + 15 - 12 = 63
3E + 3 = 63
3E=63 - 3
3E=60
E=20 EMMA receives 20
J=7.5+20
J=27.5 JUSTIN receives 27.5
M=J-12
M=27.5-12
M=15.5 EMMA receives 15.5
Let's approach this problem by slowly eliminating choices.
First consider the keyword
"at most" and
"no more than". This means that the inequality should be less than or equal to the constant value stated. This will automatically eliminate two choices with the greater than symbol favoring the variables - choices A and D.
Next we associate the right constants to the right coefficients of variables. The two kinds of weight the truck transports are 30 and 65 lbs, and we know that this should not exceed 3,800 lbs. This is therefore our first inequality. The other inequality is for the volume. The combinations of the two volumes 4 and 9 cubic feet should not exceed 400 cubic feet when transported.
If you try to construct the inequality and miss it among the choices, don't worry! Let's try doing some simplifications first and see if it matches either B or C.
After simplification you can get

from dividing the equation by 5 and

for leaving it as it is.
Looking carefully, we can see that this is equivalent to option B.
ANSWER: B.
Given that
log (x+y)/5 =( 1/2) {log x+logy}
We know that
log a+ log b = log ab
⇛log (x+y)/5 =( 1/2) log(xy)
We know that log a^m = m log a
⇛log (x+y)/5 = log (xy)^1/2
⇛log (x+y)/5 = log√(xy)
⇛(x+y)/5 = √(xy)
On squaring both sides then
⇛{ (x+y)/5}^2 = {√(xy)}^2
⇛(x+y)^2/5^2 = xy
⇛(x^2+y^2+2xy)/25 = xy
⇛x^2+y^2+2xy = 25xy
⇛x^2+y^2 = 25xy-2xy
⇛x^2+y^2 = 23xy
⇛( x^2+y^2)/xy = 23
⇛(x^2/xy) +(y^2/xy) = 23
⇛{(x×x)/xy} +{(y×y)/xy} = 23
⇛(x/y)+(y/x) = 23
Therefore, (x/y)+(y/x) = 23
Hence, the value of (x/y)+(y/x) is 23.
A = P(1+r)^(t/5) A = 500000(1+0.05)^(15/5) A = 500000(1.05)^(15/5) A = 500000(1.05)^3 A = 500000*1.157625 A = 578812.5 Telling us that the population will be about 578,812 people in the year 2005

Using the quadratic formula we get

Therefore the tennis ball is at least 15 feet above the ground from 0.5 seconds to 2.04 seconds