Algebra

posted by .

1)Find the sum of the infinite geometric series: 1 + 3/5 + 9/25 + ..., if it exists.

A)5/3
B)5/2
C)3/5
D)does not exist
I chose B

(3/5)/1 = .6
S = a1/1-r
1/1-.6
2.5

2)Use the Binomial Theorem to find the sixth term in the expansion of (m+2p)^7.

A)21m^2p^5
B)672m^2p^5
C)32m^2p^5
D)448mp^6

7/(7-k)!k!^m7-kpk
7/(7-5)!5!^m7-5p5
7*6*5*4*3/5*4*3*2*1^m2p5
2520/120
21m^2p^5

3)How many four-digit numerical codes can be created if no digit may be repeated?

A)10,000
B)24
C)3024
D)5040
I chose A

10*10*10*10
10,000

  • Algebra -

    #2 You forgot that 2 is also raised to the fifth.
    C(7,5)(m^2)(2p(^5
    = 21(2^5)m^2p^5
    =672m^2p^5

    #3. Digits may NOT be repeated, and probably cannot start with a zero.

    so 9x9x8x7 = 4536, which is none of their choices.

    if zeros would be allowed in the first position, then the answer would be
    1-x9x8x7 = 5040 which is choice D

    your choice A would include zeros, and repeating digits, even 0000,and 6666.

    I would guess that D is the choice they are after.

    #1 is ok

  • Algebra -

    typo in "1-x9x8x7 = 5040 which is choice D "

    should say:
    10x9x8x7 = 5040 which is choice D

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. algebra

    1)Find a1 in a geometric series for which Sn=300,r=-3,and n=4 a.15 b.15/2 c.-15 d.1/15 answer=a 2)Find the sum of the infinite geometric series n=1 at the bottom of the sigma notation 20(-1/4)n-1 on the right side a.25 b.80/3 c.16 …
  2. algebra(check)

    1)Find a1 in a geometric series for which Sn=300,r=-3,and n=4 a.15 b.15/2 c.-15 d.1/15 answer=a 2)Find the sum of the infinite geometric series n=1 at the bottom of the sigma notation 20(-1/4)n-1 on the right side a.25 b.80/3 c.16 …
  3. algebra

    1)Find a1 in a geometric series for which Sn=300,r=-3,and n=4 a.15 b.15/2 c.-15 d.1/15 answer=a 2)Find the sum of the infinite geometric series n=1 at the bottom of the sigma notation 20(-1/4)n-1 on the right side a.25 b.80/3 c.16 …
  4. algebra

    1)Find a1 in a geometric series for which Sn=300,r=-3,and n=4 a.15 b.15/2 c.-15 d.1/15 answer=a 2)Find the sum of the infinite geometric series n=1 at the bottom of the sigma notation 20(-1/4)n-1 on the right side a.25 b.80/3 c.16 …
  5. math

    1)Find a1 in a geometric series for which Sn=300,r=-3,and n=4 A)15 B)15/2 C)-15 D)1/15 I chose A 2)Find the sum of the infinite geometric series. Sigma sign with infinity symbol above and n=1 below. To the right 20(-1/4)n-1 A)25 B)80/3 …
  6. math(need 2nd opinion)

    1)Find a1 in a geometric series for which Sn=300,r=-3,and n=4 A)15 B)15/2 C)-15 D)1/15 I chose A 2)Find the sum of the infinite geometric series. Sigma sign with infinity symbol above and n=1 below. To the right 20(-1/4)n-1 A)25 B)80/3 …
  7. Math

    Find the sum of the infinite geometric series 36+24+16+...if it exists. r=24/36=2/3 S=a1/1-r (36)/1-(2/3) 36/.33 repeating S=108
  8. Algebra

    1. Why cant you use the formula of the infinite geometric series on 1/81 + 1/27 + 1/9 + 1/3 + ..... 2. Using concepts of infinite geometric series, show that 0.9999 ..... = 1.
  9. Pre-Calculus

    Q.Determine the sum of each infinite geometric series. t_1= 8 r = -2^1/2 ---------------------------------------- A.This is a divergent series because the absolute value of r is greater than 1. ---------------------------------------- …
  10. math

    Find the sum of the infinite geometric series below, or indicate that the sum does not exist. 15+6+12/5+24/25+...

More Similar Questions