Get Answers to all your Questions

header-bg qa

The sum of the first three numbers in an Arithmetic Progression is 18. If the product of the first and the third term is 5 times the common difference, find the three numbers.

 

Answers (1)

Met 1st three terms of AP be \mathrm{(a - d), \ a \ \text{and } (a +d)}

So,    \mathrm{a - d + a + a + d = 18}

          \mathrm{\Rightarrow a = 6}

            \mathrm{(a-d)(a+d) = 5d}

       \mathrm{\Rightarrow a^2 - d^2 = 5d}

       or   \mathrm{d^2 + 5d - 36 = 0}

              \mathrm{(d + 9 )(d-4) = 0}

               \mathrm{d = -9 \ or \ 4}

For d = 4, three numbers are 2,6, and 10

for d = -9, three numbers are 15, 6 and 3

Posted by

Safeer PP

View full answer