Topic Question Set


Q 11 :    

The number of elements in the set S={(x,y,z):x,y,zZ,x+2y+3z=42,x,y,z0} equals _______ .               [2024]



(169)

x+2y+3z=42

At z=0,x+2y=42

y can take all value from 0 to 21

Hence 22 solutions.

Similarly,

at z=1, x+2y=39    20 solutions

at z=2, x+2y=36    19 solutions

at z=3, x+2y=33    17 solutions

at z=4, x+2y=30    16 solutions

at z=5, x+2y=27    14 solutions

at z=6, x+2y=24    13 solutions

at z=7, x+2y=21    11 solutions

at z=8, x+2y=18    10 solutions

at z=9, x+2y=15      8 solutions

at z=10, x+2y=12    7 solutions

at z=11, x+2y=9        5 solutions

at z=12, x+2y=6        4 solutions

at z=13, x+2y=3        2 solutions

at z=14, x+2y=0        1 solutions

Total cases = 169 solutions.

 



Q 12 :    

Let the set C={(x,y)x2-2y=2023, x,yN}. Then (x,y)C(x+y) is equal to ________ .              [2024]



(46)

We have, x2-2y=20232y=x2-2023

  Possible values of (x,y) are (45,1)

So, (x,y)C(x+y)=(45+1)=46

 



Q 13 :    

A group of 40 students appeared in an examination of 3 subjects - Mathematics, Physics, and Chemistry. It was found that all students passed in at least one of the subjects, 20 students passed in Mathematics, 25 students passed in Physics, 16 students passed in Chemistry, at most 11 students passed in both Mathematics and Physics, atmost 15 students passed in both Physics and Chemistry, atmost 15 students passed in both Mathematics and Chemistry. The maximum number of students passed in all the three subjects is __________ .    [2024]



(10)