Mr. Koh has some pens. If he ties them in bundles of 10, he will have 4 extra pens. If he ties them in bundles of 7, he would be short of 2 pens. What is the smallest possible number of pens Mr. Koh has?
Multiples of 10: 10, 20, 30, 40, 50
Multiples of 10 (+4): 14, 24, 34, 44, 54
Multiples of 7: 7, 14, 21, 28, 35, 42, 49, 56
Multiples of 7 (-2): 5, 12, 19, 26, 33, 40, 47, 54
Smallest possible number of pens that Mr. Koh has = 54
Answer(s): 54
