a nice sum 2

Calculus Level 1

what is the answer?

29.6 55.8 25.4 27.5

4 solutions

Nihar Mahajan
Dec 28, 2014

sum of nos. from 1 to n = n * (n +1) / 2

here, n = 10

substituting n = 10 we get ,

x = 10 * 11 / 2

x = 55

so , x / 2 = 55 / 2 = 27.5 :)

A Former Brilliant Member
Apr 2, 2018

$x=1+2+3+4+5+6+7+8+9+10=55$

$\dfrac{x}{2}=\dfrac{55}{2}=27.5$

Brock Brown
Dec 28, 2014

total = 0
n = 1
while n <= 10:
    total += n
    n += 1
print "Answer:", float(total)/2

Rostam Dana
Dec 28, 2014