Petrol costing 80p a litre has a price increase of 20%. what is the cost per litre now? !

So new price of per liter petrol is 96 p

Step-by-step explanation:

Given:

Price of Petrol = 80p

Increase in price = 20%

To find :

Cost per liter = ?

Solution:

As it is given that old price of petrol is 80p

Increase in price = 20 % of Old Price

New Price = Old price + Increase in price

Now first we will find increase in price

Increase in price = 20 % of 80

It could be written as

                            =

                            =

Increase in price = 16 p

New price = old price + original price

                  = 80 p  + 16 p

                  = 96 p

So new price of per liter petrol is 96 p

where are the choices?

the largest number of the four options is 1.8 x 10-2

you have it in scientific notation.

1.80 x 10-6   = 0.00000180

1.80 x 10-4   = 0.000180 (bigger, or "less small", than the former one)

so

1.8 x 10-2       = 0.0180. as you see. the "less small", or the biggest one of them all.

as you have negative exponent, it means you are dividing 1.8 by 100 (i.e. moving the dot towards left, two times).

if you had positive exponent for the scientific notation, power of tenths, you would be multiplying times 100 (moving the dot towards right) as below:

1.8 x (10)2 = 180

so. if you have negative exponent in scientific notation, move the dot toward left. if it is positive, toward right as many times the exponent tells you.