Answered

Discover the best answers at Westonci.ca, where experts share their insights and knowledge with you. Discover in-depth answers to your questions from a wide network of experts on our user-friendly Q&A platform. Discover in-depth answers to your questions from a wide network of professionals on our user-friendly Q&A platform.

If S = [tex]\frac{n}{2}[/tex](a + L), find n when, S= 640, a = 25 and L = 39

Sagot :

semsee45

Answer:

n = 20

Step-by-step explanation:

Sum of an arithmetic series

[tex]S_n=\dfrac{n}{2}(a+l)[/tex]

where:

  • a = first term
  • l = last term
  • n = number of terms

Given:

  • [tex]S_n=640[/tex]
  • [tex]a=25[/tex]
  • [tex]l=39[/tex]

Substituting the given values into the formula and solving for n:

[tex]\implies 640=\dfrac{n}{2}(25+39)[/tex]

[tex]\implies 640 \cdot 2=n(25+39)[/tex]

[tex]\implies 1280=n(25+39)[/tex]

[tex]\implies 1280=64n[/tex]

[tex]\implies n=\dfrac{1280}{64}[/tex]

[tex]\implies n=20[/tex]

Thank you for trusting us with your questions. We're here to help you find accurate answers quickly and efficiently. Thank you for your visit. We're dedicated to helping you find the information you need, whenever you need it. We're dedicated to helping you find the answers you need at Westonci.ca. Don't hesitate to return for more.