Elitmus
Exam
Numerical Ability
LCM and HCF
If Qs are numbers less then 200 when divided by 5 or 7 leaves remainder 2.Find the sum of all Qs.
Read Solution (Total 13)
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- First find the l.c.m of 5,7=35. The no Q will be in the form 35p+2. Putting p=1,2 and so on we get the various values of Q which satisfy the above condition.putting p=1,2,3,.....5 then p will be 37,72,107,142,177 respectively...hence the sum is 535.
- 10 years agoHelpfull: Yes(41) No(6)
- 1st find for 5 u will get no like 2,7,12,......197
Sn=3980
2nd find for 7 u will get no like 2,9,17,.....198
sn=2900
find the no like 2,37,72...........=Sn =537
total = 3980+2900 - 537
= 6343
- 9 years agoHelpfull: Yes(8) No(0)
- @Ravi u should u consider 2 also , because when we divide 2/35 reminder will be 2
hence some of Qs numbers= 535+2=537 - 10 years agoHelpfull: Yes(7) No(4)
- 1st find for 5 u will get no like 7,12,......197
Sn=2277
2nd find for 7 u will get no like 9,17,.....198
sn=3978
find the no like 37,72...........=Sn =535 and sub tract the sum with both the Sn
and then add all Sn1=2277-535=1742
Sn2=3978-535=3443
Sn(final)=1742+3443+535=5720ans - 10 years agoHelpfull: Yes(6) No(8)
- general form for forming N = 35 * a +2
(lets a= 1,2,3,4,5)
so , N can be ----> 37,72,107,142,177
sum of all no is = 37 +72 +107 +142 +177 = 535 - 9 years agoHelpfull: Yes(2) No(1)
- 1>
on divide by 5
the series would be 7,12,17.........197
last digit (l)=a+(n-1)d
on solving n=39
sum of all term (sn1)=n/2[2a+(n-1)d]
=141 ;a=7, n=39,d=5
similarly
for 7
series 9,........198
(l)=a+(n-1)d
n=28
sn2=2898
now the final ans sn=sn1+sn2
=141+2989
=3039 - 10 years agoHelpfull: Yes(1) No(5)
- we know if reminder is same then,
General form=Lcm(divisor)*Y+reminder
=Lcm(5,7)*Y+2,
in questn we have to find sum of all Qs,Which is less than 200,
so there are 6 nos are there which are less than 200,
they are--->2,37,72,107,142,177 - 9 years agoHelpfull: Yes(1) No(1)
- First find the l.c.m of 5,7=35. The no Q will be in the form 35p+2. Putting p=1,2 and so on we get the various values of Q which satisfy the above condition. When p=1 Q=37. P=2 Q=72 p=3 Q=167. Sum of them = 276
- 10 years agoHelpfull: Yes(0) No(9)
- @RAYAGOUDA, its not the case of mod, its the case of division which is clearly mentioned in the que. so we cant take extra 2
- 10 years agoHelpfull: Yes(0) No(2)
- first of all we have numbers starting from 7 to 197 which gives the reminder 2 when devided 5 now as we can see the arithmetic progression so by using the formulae tn=a+(n-1)d wr the a is the starting no and d is the diffrence between the numbers now first we need to find tn means t197=7+(197-1)5=987 then to find the total sum of no mpresent in the Qs we need to apply this formulae sum of no=n/2(a+tn) i.e sum=197/2(7+987)=97909
- 10 years agoHelpfull: Yes(0) No(3)
- First find the l.c.m of 5,7=35. The no Q will be in the form 35p+2. After this put the value of p from 0,1,2
so the total sum going to be 537
- 9 years agoHelpfull: Yes(0) No(0)
- First find the l.c.m of 5,7=35. The no Q will be in the form n*35-2. put p=1,2,3,4,5. find the values and add them ..
33+68+103+138+173= 515 - 8 years agoHelpfull: Yes(0) No(0)
- 537
take LCM of 5 and 7 that is 35
and remainder is 2 so first no is 35+2 = 37
and general case is (35x+2) put the values of that satisfy the the question condition - 6 years agoHelpfull: Yes(0) No(0)
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