Question

On 1st Jan 2016,sanika decides to save 10 o second day rupees 11 on third day rupees 12.If she decides to save like this, then on 31st Dec 2016 what would be her total

Answer 1

$here \: is \: your \: answer$

ON FIRST JANUARY

she save Rs 10

Next day Rs 11

Next day Rs 12

so,money save by her = 10+11+12+13+......(till 31st dec )

Now assumption

a = 10

d = 1

n = 366 days

$sum \: of \: ap = \frac{n}{2} [2a + (n - 1)d] \\\\ = \frac{366}{2} [2 \times 10 + (366 - 1)1]\\ \\ = 70455$

Hence, she will save 70455 till end of year 2016.