Question

Aditya is celebrating his birthday. He invited his friends. He bought a packet of toffees/candies which contains 120 candies. He arranges the candies such that in the first row there are 3 candies, in second there are 5 candies, in third there are 7 candies and so on.(a) Find the total number of rows of candies.(i) 12 (ii) 10 (iii) 14 (iv) 8

(b) How many candies are placed in last row? (i) 22 (ii) 21 (iii) 24 (iv) 18 

(c) Find the difference in number of candies placed in 7th and 3rd row. (i) 8 (ii) 10 (iii) 12 (iv) 14 

(d) If Aditya decides to make 15 rows, then how many total candies will be placed by him with the same arrangement? (i) 200 (ii) 150 (iii) 255 (iv) 210 

(e) Find the number of candies in 12th row.(i) 21 (ii) 30 (iii) 25 (iv) 19

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Answer 1

Answer:

For this we have us AP

total number of rows = 10

And number of candies in last row =21

Step-by-step explanation:

If the S(Sum of the all the terms) in a series be 120

and the terms are 3,5,7,9....

S=n/2 X 2a+d(n-1)

d=2,a=3(Substitute the values to get n)

120=n/2 X 6+2(n-1)

120=n/2 X 6-2+2n

120=n/2 X 4+2n

120 =n X 2+n

$n^{2} +2n-120=0$

Solve for n u will get 10

Therefore total number of rows = 10

And number of candies in last row =21

Answer 2

Answer:

Step-by-step explanation:

As per the question:

Given That:

He purchased a package of toffees or candies that had 120 candies in it. He arranges the candy so that there are three candies in the first row, five candies in the second, seven candies in the third, and so on.

To Find:

Find the total number of rows of candies.

How many candies are placed in last row

Find the difference in number of candies placed in 7th and 3rd row.

If Aditya decides to make 15 rows, then how many total candies will be placed by him with the same arrangement

Find the number of candies in 12th row.

Solution:

For this we have us AP

total number of rows = 10

And number of candies in last row =21

Step-by-step explanation:

If the S(Sum of the all the terms) in a series be 120

and the terms are 3,5,7,9....

S=n/2 X 2a+d(n-1)

d=2,a=3(Substitute the values to get n)

120=n/2 X 6+2(n-1)

120=n/2 X 6-2+2n

120=n/2 X 4+2n

120 =n X 2+n

$n^{2} +2n-120=0$

Solve for n u will get 10

Therefore total number of rows = 10

And number of candies in last row =21

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