Request clarification:

Expert:

Please mention the question to be solved. 

User:

I need help on questions 1-20 on the day 6
And 1-10 on day 7.

Expert:

It is not possible to do that many questions, please mention one at a time. 

User:

questions from day 6

The answer is in the image 

For every 8 cars there are 7 trucks

Therefore,

Cars:Truck=8:7

Answer is B)8:7

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 

tip=18% of 75.45

     =18/100 * 75.45 = $13.581

Tip = $13.581

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

Given height of gymnasium is 5/6 height of 30 foot ball

therefore height of gymnasium=5/6 * 30

=25 feet

The solution is given below

Decrease in bikes sale = 650 - 572 = 78

%Decrease = (change)/old value * 100

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

Decrease in sale = 12%