short Tricks

Divisibility by 2 Rule Almost everyone is familiar with this rule which states that any even number can be divided by 2. Even numbers are multiples of 2. A number is even if ends in 0,2,4,6, or 8. Ex . 2 0 4 -2 -312 31,102 Divisibility by 3 Rule Add up all the digits in the number. Find out what the sum is. If the sum is divisible by 3, so is the number Ex . 12→1 + 2 = 3 And 3 is divisible by 3 so the number 12 is also divisible by 3. Divisibility by 4 Rule A number is divisible by 4 if the number's last two digits are divisible by 4. Ex . 358912 ends in 12 which is divisible by 4, thus so is 358912 Divisibility by 5 Rule A number is divisible by 5 if the its last digit is a 0 or 5. Ex . 10 → since the last digit is 0, 10 satisfies this rule and is divisible by 5 15 → since the last digit is 5, 15 satisfies this rule and is divisible by 5 45 -30 55 -105 Divisibility by 6 Rule If the Number is divisible by 2 and 3 it is divisible by 6 also. Ex .    114 → satisfies both...

Mixture and Alligation based Questions Question Type -1 In X gram mixture of milk and water, milk is P %. To make the quantity of milk in the mixture to be Q %, the quantity of milk added to the mixture will be. Trick: X{(Q-P)/(100-Q)} Ex . In a 60 liters mixture of milk and water, the quantity of milk is 5 %. In how much quantity, should milk be added to this mixture so that the quantity of milk in the mixture becomes 15 % ? Ans . Use trick- 60*{(15-5)/(100-15) 60*(10/85) 120/17 liters Question Type -2 In what ratio must a grocer mix two varieties of things costing Rs. C (Cheaper) and Rs. D(Costlier/Dearer) per kg respectively so as to get a mixture worth Rs. M kg? Trick: (Cheaper quantity) : (Dearer quantity) = (D - M) : (M - C) Ex . In what ratio must a grocer mix two varieties of pulses costing Rs. 15 and Rs. 20 per kg respectively so as to get a mixture worth Rs. 16.50 kg? Ans . Use trick- (Cheaper quantity) : (Dearer quantity) = (20-16.50):(16.50-15) (Cheaper quant...