Question

Here is a keyboard of a harmonium:
Find the ratio of white keys on the keyboard.

Answer 1

Hint: From the given diagram, count the number of blue buttons and white buttons on the keyboard. Now, calculate the total number of buttons on the keyboard by adding the number of blue buttons and white buttons on the keyboard. At last, get the ratio of white keys on the keyboard with respect to the total number of buttons.

Complete step by step answer:
According to the question, we are given a diagram of the keyboard and on the keyboard, there are some white keys whereas there are some blue keys too.
Now, from the given figure, on counting, we get
The number of white keys on the keyboard = 10 ………………………………………(1)
The number of blue keys on the keyboard = 7 ……………………………………………(2)
The total number of keys on the keyboard = The number of white keys on the keyboard + The number of blue keys on the keyboard …………………………………………(3)
On adding equation (1) and equation (2), we get
The total number of keys on the keyboard = \[10+7=17\] ……………………………………(4)
As per the question, we are asked to find the ratio of white keys on the keyboard that is, we have to find the ratio of white keys to the total number of keys on the keyboard.
The ratio of white keys = \[\dfrac{Number\,of\,white\,keys}{Total\,number\,of\,keys}\] ………………………………………..(5)
Now, from equation (1), equation (4), and equation (5), we get
The ratio of white keys = \[\dfrac{10}{17}\] .

Therefore, the ratio of white keys on the keyboard is \[\dfrac{10}{17}\]

Note: While solving this question, one might get confused because we are only asked to find the ratio of white keys on the keyboard. But, we know that ratio is always calculated with respect to something. Here, it has not been given that in whose respect the ratio is to be calculated. Therefore, if nothing is mentioned in the question then calculate the ratio with respect to the whole.