Question

without adding find the sum 1+3+5.............+31​

Answer 1

Answer:

256

Step-by-step explanation:

FORMULA : n/2[2a+(n-1)d]

Step one: find 'n'

d= 3-1 = 2

last term = a+(n-1)d= 1+(n-1)2 = 31

from this we get n=16

hence,

16/2[(2×1)+(16-1)2]= 8[2+30]= 256