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Question
primary 5 | Maths
| Whole Numbers
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Help me to solve this problem
Tom's steps :
1,3,5,7,9,11,13,15,17,19,21,23,25,27,29,31,33,35
Total steps : 18
Jerry's steps :
1,4,7,10,13,16,19,22,25,28,31,34
Total steps : 12
But notice that there are common steps.
They are 1,7,13,19,25,31.
So total number of steps
= 18 + 12 - 6 = 24
Or if they started from the ground floor ('step 0')
Tom's steps :
2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34,36
Total steps : 18
Jerry's steps :
3,6,9,12,15,18,21,24,27,30,33,36
Total steps : 12
There are common steps.
They are 6,12,18,24,30,36
So total number of steps
= 18 + 12 - 6 = 24
Tom : 36 ÷ 2 = 18
Jerry : 36 ÷ 3 = 12
The common multiple of 3 and 2 is 6
(Because 2 x 3 = 6, 3 x 2 = 6)
So every 6th step is common.
That is 6,12,18,24,30,36.
So total steps to be cleaned
= 18 + 12 - 6 = 24
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