If four distinct positive numbers, a, b, c and d, in the order given are in proportion, then which of the following options is NOT correct?

If all the girls in school B and school C participated in the function, find the ratio between the number of boys in school B and school C who participated in the function.

Which of the following examples represents an inverse proportional relationship (reverse movement)?

The ratio of the present ages of Ajay and Atul is 5 : 6. If after 20 years the ratio of their ages becomes 9 : 10, what is the difference between their present ages?

Find the ratio of investment in Defence sector to Health sector if the allocation amounts are in the ratio of 2 : 3 respectively.

Find the ratio of qualified candidates from Madhya Pradesh, Maharashtra, and Rajasthan together to the appeared candidates from Andhra Pradesh, Gujarat, and Delhi together.

Find the ratio of qualified candidates from Gujarat to the appeared candidates from Rajasthan.

Find the mean proportion between 48 and 75.

Due to a water crisis, 40% of the initial population left the village and 35% of the remaining population left the village to pursue jobs. If 2340 people presently inhabit the village, what is the ratio of the initial population to the present population?