Exams

Ratio of times taken by P & Q = 100 : 130 = 10:13

Let Q takes x days to do the work

Then, 10:13 :: 23:x

=> x = 23x13/10

=> x = 299/10

P's 1 day's work = 1/23

Q's 1 day's work = 10/299

(P+Q)'s 1 day's work = (1/23 + 10/299) = 23/299 = 1/13

Hence, P & Q together can complete the work in 13 days.

Papayas are yellow due to the presence of carotene and xanthophyll pigments i.e, Caricaxanthin present in the chromoplasts of the fruit pulp.

The coloration of the different tissues in plants is due to the plastids which are present in the cells. Leucoplasts are white in colour, chloroplasts are green in colour and chromoplasts are of various colours. These plastids can take any colour at different time. Therefore, green fruits ( chloroplasts) turn colurful (chromoplasts) at maturity.

Given taps X and Y can fill the tank in 30 and 40 minutes respectively. Therefore,

part filled by tap X in 1 minute = 1/30

part filled by tap Y in 1 minute = 1/40

Tap Z can empty the tank in 60 minutes. Therefore,

part emptied by tap Z in 1 minute = 1/60

Net part filled by Pipes X,Y,Z together in 1 minute = [1/30 +1/40 - 1/60] = 5/120 = 1/24

i.e., the tank can be filled in 24 minutes.

After 5 mins ..... 3 persons will get rumour
After 10 mins .... 3x2 + 3 = 9 = 32 persons will get
after 15 =5x3 min ......9x2 + 9 =27 = 33 persons will get news.
.
.
after 5x6 mins ... 36 = 729 persons will get news.

Therefore, time taken to spread the rumour to 729 persons is 30 minutes.