At a certain temperature the population of a bacteria culture doubles every 3 hours. If the initial population of the culture is 100 cells, how many bacteria are there after 2 days?
This is one of the questions that I’m not good at.

The answer is in the image 

The solution is in the following image

The answer is in the image 

The wood before starting =12 feet

Left wood=6 feet

Wood used till now=12-6=6 feet

Picture frame built till now= 6/(3/4)

=8 pieces

Therefore, till now 8 pieces have been made.

The answer is in the image 

Let the father's age be x and son's be y

10 years before-

Father age=x-10

sons age=y-10

Given,

x-10=10(y-10)

x-10=10y-100

Given present age of father=40

therefore,

x=40

40-10=10y-100

10y-100=30

10y=130

y=130/10

y=13

Therefore present age of son=13years

Cost before sale tax=$46.00

Cost after including tax=$48.76

Sale tax=$48.76-46.00

=$2.76

we know,

sale tax=((sales tax rate)/100) * cost before sale tax

2.76=((sales tax rate)/100) *46.00

sale tax rate=(2.76*100)/46

                   =276/46

                    =6%

There fore sales tax rate=6%

We can put the numbers in ascending order-

36, 38, 39, 39, 40, 47, 48, 51

Range=max-min

          =51-36

          =15

Weight of adult elephant = 24,000 pounds

Weight of baby elephant = 260 pounds

Difference between weight = 24,000 - 260 = 23,740

Adult elephant weights 23,740 pounds more 

Decrease in bikes sale = 650 - 572 = 78

%Decrease = (change)/old value * 100

%Decrease in sale = 78/650 * 100 = 12%

Decrease in sale = 12%