Exams

Let A worked for x days.

x/21 + 4/28 = 1  => x = 18

A worked for 18 days. So, A can complete the remaining work in 18 - 4 = 14 days.

Train becomes trail when the "n" is replaced by an "l", and grain becomes grail when the "n" is replaced by an "l".

Given that,

Members in football team = n(f) = 10

Members in science club = n(s) = 14

Members in both football team and science club = n(f ^ s) = 5

Then, Members in only football team = n(F) = 10 - 5 = 5

Members in only science team = n(S) = 14 - 5 = 9

Hence, members in only football or science team = n(FUS) = n(F) + n(S) - n(f^s) 

= 9 + 5 - 5

= 9.

Hence, many students belong to only science club team or football team = 9.

8 S on SS means 8 Sides on a Stop Sign.

This is one type of Letter Equations which are well known phrases or facts where the key words have been replaced with the first letter of that word. These are often in the form of an equation, which contain a number, an = sign and the rest of the obscured phrase or fact.

Some more of them are ::

90 D in a RA

26 L of the A 

12 S of the Z.

20 large cakes will require the equivalent of 10 helpers working for one hour. 700 small cakes will require the equivalent of 20 helpers working for one hour. This means if only one hour were available we would need 30 helpers. But since three hours are available we can use 10 helpers.

Gold coins = 18000 , Silver coins = 9600 , Bronze coins = 3600

Find a number which exactly divide all these numbers 

That is HCF of 18000, 9600& 3600 

All the value has 00 at end so the factor will also have 00.

HCF for 180, 96 & 36.

Factors of  

180 = 3 x 3 x 5 x 2 x 2

96 = 2 x 2 x 2 x 2 x 2 x 3 

36 = 2 x 2 x 3 x 3 

Common factors are 2x2×3=12

 Therefore, Actual HCF is 1200

Gold Coins 18000/1200 will be in 15 rooms

Silver Coins 9600/1200 will be in 8 rooms

Bronze Coins 3600/1200 will be in 3 rooms

Total rooms will be (15+8+3)  =  26 rooms.