A set of 30 consecutive natural numbers is divided into two subsets, A and B. In set A there are 15 consecutive natural numbers whereas the rest are in set B. If the average of the numbers in set B is 83, what is the last number in set A?
Answers
Answer:
Answer:
(a
2
−b
2
) is divisible by 3
i.e (a−b)(a+b) is divisible by 3.
Case(1) (a+b) is divisible by 3
If a is chosen from (3k+1) set ,then b must be from (3k+2) set and viceversa.
If a is chosen from (3k) set, then b must be from (3k).
So, number of ways = 10*10
Note that when a is from 3k and b is from 3k,
then (a−b) is also divisible by 3.
Case(2) (a−b) but not (a+b) is divisible by 3
If a is chosen from (3k+1) set ,then b must be from (3k+1) set .
Same for (3k+2) set.
So, number of ways = 2* 10*10
Number of ways of choosing such that a,b such that (a
2
−b
2
) is divisible by 3
=30*30
Probability
=
30×30
5×10×10
=
9
5
Step-by-step explanation:
hope u ike
THANKS
0
0.0
(0 votes)
Log in to add comment
Still have questions?
FIND MORE ANSWERS
ASK YOUR QUESTION
New questions in Math
After plotting the points find out which of thefollowing points are collinear.(a) A(-3, 2), B(0, 2) and C(0, -3)
x+9 x+3 the length is double the width
find the value of ( 49)/49
only for girl showing penis qvc-xwkb-kfqhelp
if the triangle is 42 and 2 sides are 18 cm and 10 cm ,then find its area in which chapter this question is of NCERT
divide 100 between 2 friends so that one gets 9 rupess less than other
weight of some wheat bag is 1743 k g.if one of the number is -30 find the number of bags.
find the median of the data 25, 38, 47, 19 ,18 ,26, 35 ,40
what is the equivalent fraction of 8/11 having the numerater 40
LIa) A Gb) AEGC) A>Gd) None of thesev) If the roots of the equation x² + 8x - (2k + 3) -0 differ by 2, then value of k isa) -9b) -6c) 9d) 6
Previous
Next
Ask your question