2^x - 2^x-2 = 3(2^13), what is x?
2^x(1-1/4)= 3(2^13)
2^x(3/4)= 3(2^13)
3(2^x-2)= 3(2^13)
x-2=13
x=15

x - is the quantity of solution
.76x+200=0.84x

solving we get x = 400

To weaken , we need to prove that overcrowding is not the only reason for the decline in reading skills. i was stuck between D and E D. it says, there are other cities which are crowded as Gotham, where the reading skills have not declined. So crowing is not the reason E. says in some less crowded p...

x + 2y + 3z = 2 - (1)

x + y - z = 0 - (2)

2x + 2y - z = 1 - (3)


eq 2 gives x +y=z - (4)

put value of eq4 in eq 3

2z - z =1 => z = 1

putting value of z in eq 1 we get x + 2y= -1 - (5)

putting value of z in eq 4 we get x + y= 1 - (6)

eq(5) - eq (6)
y = -2

there are two unknown variables x and n which should be found for giving value of t. using option 1 - we cannot find value of only one variable. either x or n and not both using option 2 - we can find value of x. but still n is unknown Option C is correct. because both options help us in finding x a...