Elitmus
Exam
Numerical Ability
Algebra
if a1=139/3, a2= -19 and ak= ak-1 - ak-2 , then what will be 62th term in the series ? (k, k-1, k-2 are in base of a)
a. 139/3
b. -19
c. -196/3
d. -19-139/3(-19-196/3)
Read Solution (Total 4)
-
- a1=139/3
a2=-19
a3=a2-a1=-19-139/3=-196/3
a4=a3-a2=-196/3-(-19)=-139/3
a5=a4-a3=-139/3-(-196/3)=57/3
a6=a5-a4=57/3-(-139/3)=196/3
a7=a6-a5=196/3-57/3=139/3=a1
a8=a7-a6=139/3-196/3=-57/3=-19=a2
The series repeats after every 6 numers.
Thus 62nd number=6*10+2=2nd number= -19 - 7 years agoHelpfull: Yes(32) No(0)
- Given:-
a1=139/3
a2=-19
ak= ak-1 - ak-2
Now Put (K=3,4,5,6,7,8.......);
a3=a2-a1=-19-139/3=-196/3
a4=a3-a2=-196/3-(-19)=-139/3
a5=a4-a3=-139/3-(-196/3)=57/3
a6=a5-a4=57/3-(-139/3)=196/3
a7=a6-a5=196/3-57/3=139/3=a1
a8=a7-a6=139/3-196/3=-57/3=-19=a2
Now we can easily see cycle is repeatng after 6 terms
So 62%6=2 (Remainder)
Here remainder is 2
and second term of cycle is -19
Ans:-> -19 - 7 years agoHelpfull: Yes(4) No(0)
- a1=139/3
a2=-19
a3=-19-139/3
a4=-139/3
a5=19
a6=19+139/3
a7=139/3
a8=-19
a9=-19-139/3
......
a2=a8=a14=...=a62=-19 - 7 years agoHelpfull: Yes(1) No(1)
- a1=139/3
a2=-19
a3=-19-139/3
a4=-139/3
a5=19
a6=19+139/3
a7=139/3
a8=-19
Here cyclicity=6;
so a62=a2=-19 - 7 years agoHelpfull: Yes(1) No(1)
Elitmus Other Question
1/x + 1/y = 1/z, if x =12 and y and z are whole numbers. find the no of solutions possible?
there are seven persons A,B,C,D,E,F,G (not in order) whose age are 40, 45, 50, 56, ,58, 64, 69 ( not in order) birthdays are in the months from february to september, there is one blank month in which no birthday occurs.
1. A's birthday is just one month before G and A is less than 50 years.
2. C's birthday comes before G.
3. there are two birthday's between D and E. age of E is 45 and age of D is (dont remember).
4. there are two months after A including 1 blank month. there is exactly 5 years gap between the age of persone just before blank month and just after blank month.
5. B's birthday comes just before F. F's age was 69 years.
Q1- in March whose birthday comes?
Q2. Which two months have max age?
Q3. what is the age difference between A and G?