Four numbers are in AP. The sum of the first three is 21 and the sum of last three is 30 . Find the numbers
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that's the answers..find the numbers yourself as I am busy
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Here is your solution
Given :-
Sum of first 3 numbers = 21
a + a + d + a + 2d = 21
⇒ 3a + 3d = 21
⇒a + d = 7 ---------------( 1 )
The sum of last three number is 30
⇒ a + d + a + 2d + a + 3d = 30
⇒3a + 6d = 30
⇒a + 2d = 10--------------( 2 )
on subtracting equation ( 1 ) from ( 2 )
a + d - a -2d = 7 -10
-d = -3
d = 3
putting the value of d in equation (1)
a + 3 = 7
a = 7 - 3
a = 4
d = 3
The numbers are
a = 4 , (a + d) = 7✔
(a + 2d) = 10✔
(a + 3d) = 13✔
AP are 4 , 7 , 10 , 13 .
Hope it helps you
Given :-
Sum of first 3 numbers = 21
a + a + d + a + 2d = 21
⇒ 3a + 3d = 21
⇒a + d = 7 ---------------( 1 )
The sum of last three number is 30
⇒ a + d + a + 2d + a + 3d = 30
⇒3a + 6d = 30
⇒a + 2d = 10--------------( 2 )
on subtracting equation ( 1 ) from ( 2 )
a + d - a -2d = 7 -10
-d = -3
d = 3
putting the value of d in equation (1)
a + 3 = 7
a = 7 - 3
a = 4
d = 3
The numbers are
a = 4 , (a + d) = 7✔
(a + 2d) = 10✔
(a + 3d) = 13✔
AP are 4 , 7 , 10 , 13 .
Hope it helps you
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