Question

★ moderators
★ brainly stars
★ other best users

A pack card contains n cards numbered from 1 to n. Two consecutive numbered cards are removed from the pack and the sum of the numbers on the remaining cards is 1224 . If the smaller to the numbers on the removed cards is k, then find k - 20.

(jee advanced 2013)

I won't hesitate to report your id if you spam ​

Answer 1

Answer:

Sum of 1st n natural nos. =2n(n+1)

Given: 2n(n+1)−(k+k+1)=1224

⇒ 2n(n+1)−2k=1225....(1)

also

2n(n+1)−(2n−1) (when k=(n−1) <1224<2n(n+1)−3 (when k=1)

2(n2−3n+2)<1224<2(n2+n−6)

(n−2)(n−1)<1448<(n−2)(n+1)

So n=50 by wt and trial method

So in equation (1) (51)(250)−2k=1225

1275−2k=1225

k=25

k−20=5 (Ans)

hope this helps army

sarangheyo

borahae

Answer 2

Answer:

5 is the answer