EXERCISE3.7 PROBLEM SUMS (POST-2)

Today we are going to do Ex 3.7, Q3 and Q4 

Q4. Determine the smaller 3 digit number which is exactly divisible by 68 and 12?

[Hint: Look at the words highlighted it tells us to find the LCM]

Answer: 2| 6, 8, 12

               3| 3, 4, 6

               2| 1, 4, 2 

               2| 1, 2, 1 

         LCM = 3 x 2 x 2 x 2

                   = 24

Multiples of 24 are 

24 x 1 = 24 

24 x 2 = 48

24 x 3 = 72

24 x 4 = 96

24 x 5 = 120

120 is the smallest 3 digit number divisible by 6, 8 and 12.

                                                OR

Answer: 2| 6, 8, 12

               3| 3, 4, 6

               2| 1, 4, 2 

               2| 1, 2, 1 

         LCM = 3 x 2 x 2 x 2

                   = 24

             _____

         24)100   (4

             -  96

                  4

24 - 4 = 20

100 + 20

120

Q3. The length, breadth and height of a room are 825 cm and 675 cm and 450 cm respectively. Find the longest type which can measure the 3 dimensions of the room exactly.

[Hint: Here we will find the HCF of 825 cm, 675 cm and 450cm]

                                __________

Answer: 675) 8 2 5 ( 1

                              - 6 7 5             

                         1 5 0) 6 7 5 ( 4

                                    6 0 0 

                                       7 5 )1 5 0( 2

                                               1 5 0 

                                                  0 

                    75 ) 4 5 0( 6

                         - 4 5 0 

               HCF       7 5  

Long tape that can measure the 3 dimensions of the room exactly is 75 cm.

Do these sums on your own in your copy.

Q1. Determine the longest tape that can be used to measure exactly the lengths, 84 cm, 1m 38cm and 12m.

[Hint: convert to cm and then workout the sums]

Q2. There are 3 heaps of rice weighing 120 Kg, 144 Kg and 204Kg. Find the maximum capacity of a bags so that the wheat of each can be pached in exact number of bags.

Q3. Find the least 5 digit number exactly divisible by 20, 25 and 30 

Q4. Find the smallest 4 digit number exactly divisible by 5, 6, 4 and 3.

Check your answers below:

Q1. 6cm 

Q2. 12Kg

Q3. 10200

Q4. 1020

Thankyou boys 

Have a nice day.