A train is moving at a uniform speed of 80 kilometre per hour. a) how far will it travel in 15 minutes
b) find the time required to cover a distance of 250 km. { as per direct and inverse propositions}.

A train is moving at a uniform speed of 80 kilometre per hour.

a) how far will it travel in 15 minutes

b) find the time required to cover a distance of 250 km. { as per direct and inverse propositions}.

a)

Given that the train is moving at a uniform speed of 80 km/h.

Time taken = 15 minutes

First we will convert the time

Now we will calculate the distance

We know,

Substituting the values in the given formula

Distance covered in 15 minutes = 20 km

b)

Given that the train is moving at a uniform speed of 80 km/h.

Distance covered = 250 km

Calculating the time

We know,

Substituting the values in the given formula

The total nom of  code that can be used is equal to 5+3 = 8

y=2x+15

where y=Value of coin

x=Age in years

Value of coin after 19 years=2*19+15

=$53

Therefore, Value after 19 years=$53

The answer is in the image 

The solution is given in the image below

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.

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

Volume of rectangular prism=length * width * height

Given,

length=3/8cm

breadth=5/8cm

height=7/8cm

therefore volume=(3/8)*(5/8)*(7/8)

                           =105/512 cm3