Question

15 persons went to a hotel for taking their meal. 14 of them spent Rs.10 each on their meal. Average of 15 persons is Rs.11. What is the amount spent
by 15th person?​

Answer 1

$\bf\purple {QuestioN:-}$

15 persons went to a hotel for taking their meal. 14 of them spent Rs.10 each on their meal. Average of 15 persons is Rs.11. What is the amount spent by 15th person?​

$\bf\green{AnsweR:-}$

Total number of persons = 15

Amount spent by each of the first 14 people = Rs.10

Average given = Rs. 11

Amount spent by 15th person = ??

As we know,

$\Large{\boxed{\bf{Average=\dfrac{Sum\:of\:observation}{No.\:of\:observation}}}}}}$

Let the amount spent by the 15th person be X.

Then,

$\red\longrightarrow\bf{Average=\dfrac{Total\:money}{Total\:no.\:of\:people}}$

$\red\longrightarrow\bf{11=\dfrac{14\times10+X}{15}}$

$\red\longrightarrow\bf{11=\dfrac{140+X}{15}}$

$\red\longrightarrow\bf{11\times15=140+X}$

$\red\longrightarrow\bf{165=140+X}$

$\red\longrightarrow\bf{165-140=X}$

$\red\longrightarrow\bf{25=X}$

∴ X = 25.

Then, the amount spent by the 15th person is Rs. 25.

Happy Learning!!