The sum of the first 9 terms of an AP of daily temperatures (in °C) is 162.
The sum of the first 12 terms is 288.
Find the first term of the AP.

Question

The sum of the first 9 terms of an AP of daily temperatures (in °C) is 162. The sum of the first 12 terms is 288. Find the first term of the AP.

Accepted Answer

2. S9 = 9/2(2a+8d) = 162 gives 2a+8d = 36. S12 = 12/2(2a+11d) = 288 gives 2a+11d = 48. Subtract: 3d = 12, d = 4. Then 2a+8(4) = 36, 2a = 36-32 = 4, a = 2.

The sum of the first 9 terms of an AP of daily temperatures (in °C) is 162.
The sum of the first 12 terms is 288.
Find the first term of the AP.

Step-by-Step Solution

Master this chapter in 30 minutes a day.

More Class 10 AP Word Problems practice

The sum of the first 9 terms of an AP of daily temperatures (in °C) is 162.The sum of the first 12 terms is 288.Find the first term of the AP.

Step-by-Step Solution

Master this chapter in 30 minutes a day.

More Class 10 AP Word Problems practice

The sum of the first 9 terms of an AP of daily temperatures (in °C) is 162.
The sum of the first 12 terms is 288.
Find the first term of the AP.