Question

In a class of 120 students numbered 1 to 120, all even number students opt for physics, whose number are divisible by 5 opt for chemistry & those whose no are divisible by 7 opt for math. How many opt for none of these subjects?

Answer 1

79 do not opt for these subjects

Answer 2

u hv 24 multiples of 5 from 1 to 120
n 17 multiples of 7
so 120 - (24+17) = 79

Answer 3

what about even numbered students isnt there 60 of these?

Answer 4

there are 60 even numbers ...hence 60 physics student..
then 12..opt for chemistry...as 5 ,15,25,.....115(we cann't select 10,20..as it is even and seleccted in physics)
we have 17*7=119 ..i.e 17 but we cann't take 35,70,105...because they are selected earlier
hence rest are=120-(60+12+14)=120-86=34

Answer 5

we have 17 ...7 but as 35,70,105 is not ther hence 14...deducted

Answer 6

lol - this is harder than it seems

Answer 7

yep prashant - u r right

Answer 8

this question was hard...

Answer 9

nobody give right answer
someone reach at last but not find correct answer

Answer 10

ohh god!!

Answer 11

i hope any one give true answer

Answer 12

Sorry I misread the question in a hurry
Is 41 the right answer???

Answer 13

u r right prashant tell me explenation

Answer 14

there r 60 even numbers between 1 n 120
there r 24 numbers divisible by 5 between 1 n 120. however 12 of them end in 0 so r even numbers and so ruled out. so multiples of 5 left r 12.
there r 17 multiples of 5 between 1 n 120. however 8 of them r multiples of 2 and 2 r multiples of 5. so multiples of 7 left r 7.
total works out to 60 + 12 + 7 = 79
so left r 120 - 79 = 41

Answer 15

ya harkirat is right....although my approach is right...but i did mistake in case of 7....
there are some even like 28,42...are removed....

Answer 16

good solution master

Answer 17

U r welcome, i was in great the first time around n misread.....☺

Answer 18

ok genious

Answer 19

prashant your approch also right but at the end u doing mistake

Answer 20

harkirat i expect from u that u solve my unanswered question...........its level is too much high........try it

Answer 21

the one about factors ????

Answer 22

yes it is to much typical?
and also there one of mangoes problem