algebra
posted by drew .
Find S10 for (1) + (7) + (13) + (19) +...
A. 250
B. 280
C. (23)
D. 132
C.

a = 1
d = 6
n = 10
sum(10) = (10/2)(2 + 9(6))
= 5(56) = 280
looks like B)
Respond to this Question
Similar Questions

Math
Two perpendicular diamters(cutting each other at right angles) of a circle cut the circumference at four(4) points. A square is formed by joining the 4 points. If the circumference of the circle is 132cm, find the area of the square. … 
math(Urgent)
1) The number of bacteria N in a culture is given by N=250e^kt where t is the time in hours. If N = 280 when t=10 estimate the time required for the population to double in size. 280 = 250e^10k divide by 250 1.12 = e^10k ln 1.12 / … 
math(Urgent)
1) The number of bacteria N in a culture is given by N=250e^kt where t is the time in hours. If N = 280 when t=10 estimate the time required for the population to double in size. 280 = 250e^10k divide by 250 1.12 = e^10k ln 1.12 / … 
math
1) The number of bacteria N in a culture is given by N=250e^kt where t is the time in hours. If N = 280 when t=10 estimate the time required for the population to double in size. 280 = 250e^10k divide by 250 1.12 = e^10k ln 1.12 / … 
(Please help) Math
1) The number of bacteria N in a culture is given by N=250e^kt where t is the time in hours. If N = 280 when t=10 estimate the time required for the population to double in size. 280 = 250e^10k divide by 250 1.12 = e^10k ln 1.12 / … 
math30
The sum of the first 10 terms of the geometric sequence 4, 6, 9,..., to the nearest tenth, is; The answer is: For the geometric series a=4, r=1.5 or 3/2, n=10. Sn= a(r^n  1)/r  1 S10= 4((1.5)^10  1)/1.5  1 S10= 90.7 My … 
algebra
Find S10 for 2 + 5 + 8 +... A. 155 B. 152 C. 255 D. 135 I say A. 
Math
350 is 70% of what number? A) 500 B) 420 C) 245 D) 280 What percent of 64 is 24? 
Math  Are they right?
350 is 70% of what number? A) 500 *** B) 420 C) 245 D) 280 What percent of 64 is 24? 
Stats
A class consists of 50 women and 82 men. If a student is randomly selected, what is the probability that the student is a woman?