How many biscuits had it eaten on the first day?

Question

Gauri's puppy was growing fast. In the first five days since she got it it had eaten 100 dog biscuits. If each day it had eaten 6 more than the previous day .
How many biscuits had it eaten on the first day?

Answer 1

Let a be the # of Biscuits eaten 1st day.

So.

a + (a+6) + (a+6+6) + (a+6+6+6) + (a+6+6+6+6) = 100
5a + 60 = 100

Thus,

a =  8 Biscuits.

Answer is 8 Biscuits

Answer 2

....................8...............