Community technical college
posted by Benjamin .
Given that 1st term of an A.P is 7 and it's 10th term is twice the second term,calculate the (a) 19th term (b)sum of 28 terms (c) difference between 9th and 6th terms

Statistics??
What's the SUBJECT?? 
a10=a1+r(101)
14=7+r(9)
r=7/9
check
7, 7 7/9, 7 14/9, 7 21/9, 7 28/9, 7 35/9, 7 42/9, 7 49/9, 7 56/9, 14
Use the formulas for sum, knowing r, a1 
1st term=7 2nd term=a+d
10term=a+9d
7+9d=2(14+2d)
147=9d2d
7=7d=d=1
sum of 28 term
n/2(2a+(n1)d)
28/2(2*7+(281)1)
14(14+27)=14(41)
25term=574
9th term=7+(91)1
7+(91)
7+8=15
6th term=7+(61)1
7+(61)=7+5=12
9th term6th term=1512=3.
Respond to this Question
Similar Questions

arithmetic
THE SUM OF THE 2ND AND 5TH TERMS OF AN A.P IS 42. IF THE DIFFERENCE BETWEEN THE 6TH AND 3RD TERM IS 12, FIND THE: COMMON DIFFERENCE, 1ST TERM, 20TH TERM. 
arithmetic progression
given that the first term of an Ap is 7 and its 10th term is twice the second term calculate the 19th term. 
arithmetic
given that the first term of an Ap is 7 and its 10th term is twice the second term. calculate the sum of the 28 term. 
Math
Name School Team Event 3: Logic and Reasoning (with calculators) 5th/6th grade Math Meet ‘08 For each number pattern, fill in the next five terms. (2 pts. each blank) ANSWER KEY 1st term 2nd term 3rd term 4th term 5th term 6th term … 
maths
Given that the first term of an A.P is 7 and its 10th term is twice its second calculate a)19th term b) sum of 28 term c) different between the 9th and 6th term 
arithmetic
Determining the first three terms of an ArithmetiC progressionof which the (a.)10th term is 31 and the 15th term is 49 (b.)7th term is 3 and 12th term is 3 (c.)5th term is 8 and the 11th term is 28 (d.)9th term is7+9x and d=2x,Show … 
mathematics
the 10th term of an arithmetic sequence is equal to the sum of 40 and 5th term.If the 15th term is 127 what is its common difference? 
algbebra
The fifth term of an A.p. Exceeds the second term by 1.The tenth term exceeds twice the fourth term by 3 * find first term and common difference * sum of first twentyfive terms. 
algebra
If an A.p. Fifth term exceeds twice second term by 1. The tenth term xeceeds twice fourth term by 3 * find first term and common difference * find sum of first twentyfive terms. 
algebra
The fifth term of an A.P exceeds twice the second term by 1.The tenth term exceeds twice the fourth term by 3. Find:1.the first term. 2.the common difference. 3.the sum of first twenty five terms.