Question

sum that the sum of an ap wose first tarm is a, the second term is b and the last term is c is equal to {a+c}b+c_2a/2{b_a}​

Answer 1

first term =a

second term =b

last term =c

common difference=(b-a)

tn =a+(n-1) d

c=a+(n-1) d

(c-a)=(n-1)(b-a)

(c-a)/(b-a)+1=n

( c+b-2a)/(b-a)=n--------------------(1)

now ,

we know sum of n terms=n/2 (first term+last term)

put equation (1)value

= (b+c-2a)/(b-a)(a+c)

hence Sn=[(b+c-2a)(c+a)/(b-a)]

Answer 2

Rakesh had 10 candies mohit had 2x candies more than rakesh mukesh had x candies less than mohit.a how many candies did mukesh have ? express the answer in term of x. if the x=4 find the number of candies mukesh had.