Given,
CP of cosmetics = Rs 360 per dozen
SP of a pair of cosmetics = Rs 80
To find,
The gain percent
Solution,
1 dozen = 12 items
CP of 1 cosmetic = 360/12 = Rs 30
SP of 1 cosmetic = 80/2 = Rs 40
Profit = SP-CP
= Rs 40 - Rs 30
= Rs 10
Profit percentage is given by :

So, the profit percentage is 33.34%.
2464829438
The next number is 2,464,829,439
The total amount will be
total = (125.6 L) + ((125.6 +5.34) L) = (2*125.6 +5.34) L
total = 256.54 L
There are 2 ways you can write this.
You can either do /1 or /100

The most used is
This is the equation. Try it for yourself and see if it works.
C= n x 4