In an AP the seventh term is 38 and the twelfth term is 63. What is the sum of the first twenty terms?
1 answer:
Answer: 1110
Step-by-step explanation:
For an arithmetic progression, the nth term is gotten by using the formula:
= a + (n-1)d
Therefore,
7th term = a + 6d = 38 ..... equation i
12 term = a + 11d = 63 ...... equation ii
Subtract equation i from ii
(a + 6d) - (a + 11d) = 38 - 63
-5d = -25
d = 25/5
d = 5
Since d = 5
From a + 6d = 38
a = 38 - 6d
a = 38 - (6×5)
a = 38 - 30
a = 8
The sum of the first 20 terms will be:
= n/2[2a + (n-1)d]
= 20/2[(2×8) + (20-1)5]
= 10[16+(19 × 5)]
= 10(16+95)
= 10(111)
= 1110
You might be interested in
Answer:
The answer is 15
Step-by-step explanation:
f(x) = -4x + 3, f(-3)
f(-3) = -4x + 3
f(-3) = -4(-3) + 3
f(-3) = 12 + 3
f(-3) = 15
Thus, The answer is 15
Answer : C
6 2 over 3 units
Answer:
Yes, because there are 9 grid squares on one side, 16 grid squares on the other side, and 25 grid squares on the hypotenuse, and 9 + 16 = 25.
<3
A fraction is in it's simplest form if both of the numerator and denominator are not divisible by a number.
Likely best describes the likelihood of the probability 2/3. It is not completely certain, nor is it unlikely, and it definitely cannot be impossible.
