CAT: AlgebraProgression & Series. Free, no login required.

Q1:

CAT 2019 Slot 1

Progression & Series

Medium

If a1,a2….a_{1}, a_{2} \ldots .. are in A.P., then, 1a1+a2+1a2+a3+….+1an+an+1\frac{1}{\sqrt{a_{1}}+\sqrt{a_{2}}}+\frac{1}{\sqrt{a_{2}}+\sqrt{a_{3}}}+\ldots .+\frac{1}{\sqrt{a_{n}}+\sqrt{a_{n+1}}} is equal to

Answer options
Option 4
Correct Answer
Explanation for CAT 2019 Slot 1 QA question 1

Q2:

CAT 2019 Slot 1

Progression & Series

Medium

If the population of a town is pp in the beginning of any year then it becomes 3+2p3+2 p in the beginning of the next year. If the population in the beginning of 20192019 is 10001000 then the population in the beginning of 20342034 will be

Answer options
Option 1
Correct Answer
Explanation for CAT 2019 Slot 1 QA question 2

Q3:

CAT 2018 Slot 2

Progression & Series

Hard

The value of the sum 7×11+11×15+15×19+⋯+95×997 \times 11 + 11 \times 15 + 15 \times 19 + \dots + 95 \times 99 is

Answer options
Option 3
Correct Answer
Explanation for CAT 2018 Slot 2 QA question 3

Q4:

CAT 2018 Slot 2

Progression & Series

Medium

Let t1,t2,…t_1, t_2, \dots be real numbers such that t1+t2+⋯+tn=2n2+9n+13t_1 + t_2 +\dots+ t_n = 2n^2 + 9n + 13, for every positive integer n≥2n\ge2. If tk=103t_k =103, then kk equals

Q5:

CAT 2018 Slot 1

Progression & Series

Medium

Let x,y,zx, y, z be three positive real numbers in a geometric progression such that x<y<zx<y<z. If 5x,16y5 x, 16 y, and 12z12 z are in an arithmetic progression then the common ratio of the geometric progression is

Answer options
Option 3
Correct Answer
Explanation for CAT 2018 Slot 1 QA question 5

Q6:

CAT 2017 Slot 2

Progression & Series

Medium

Let a1,a2,a3,a4,a5a_1, a_2, a_3, a_4, a_5 be a sequence of five consecutive odd numbers. Consider a new sequence of five consecutive even numbers ending with 2a32a_3.

If the sum of the numbers in the new sequence is 450450, then a5a_5 is

Q7:

CAT 2017 Slot 2

Progression & Series

Medium

An infinite geometric progression a1,a2,a3,...a_1, a_2, a_3,... has the property that an=3(an+1+an+2+....)a_n = 3(a_{n+1} + a_{n+2} +....) for every n≥1n \ge 1. If the sum a1+a2+a3+.....=32a_1 + a_2 + a_3 +..... = 32, then a5a_5 is

Answer options
Option 3
Correct Answer
Explanation for CAT 2017 Slot 2 QA question 7

Q8:

CAT 2017 Slot 2

Progression & Series

Medium

If a1=12×5,a2=15×8,a3=18×11\mathrm{a}_{1}=\frac{1}{2 \times 5}, \mathrm{a}_{2}=\frac{1}{5 \times 8}, \mathrm{a}_{3}=\frac{1}{8 \times 11}, then a1,+a2,+a3,+…..a100\mathrm{a}_{1,}+\mathrm{a}_{2,}+\mathrm{a}_{3,}+\ldots . . \mathrm{a}_{100} is

Answer options
Option 1
Correct Answer
Explanation for CAT 2017 Slot 2 QA question 8

Q9:

CAT 2017 Slot 1

Progression & Series

Easy

If the square of the 77th term of an arithmetic progression with positive common difference equals the product of the 33rd and 1717th terms, then the ratio of the first term to the common difference is

Answer options
Option 1
Correct Answer
Explanation for CAT 2017 Slot 1 QA question 9

Q10:

CAT 2017 Slot 1

Progression & Series

Medium

Let a1,a2,……...a3na_{1}, a_{2}, \ldots \ldots . . . a_{3 n} be an arithmetic progression with a1=3a_{1}=3 and a2=7a_{2}=7. If a1+a2+….+a3n=1830a_{1}+a_{2}+\ldots .+a_{3 n}=1830, then what is the smallest positive integer mm such that m(a1+a2+….+an)>1830m\left(a_{1}+a_{2}+\ldots .+a_{n}\right)>1830 ?

Answer options
Option 2
Correct Answer
Explanation for CAT 2017 Slot 1 QA question 10