Question

Three points A, B, C are on the same straight line. If AB = 5 cm 6 mm and AC = 10 cm 2 mm. Then BC =?

• A. 2 cm 4 mm
• B. 12 cm 5 mm
• C. 4 cm 6 mm
• D. 6 cm 4 mm

Answer 1

The correct option is C

4 cm 6 mm

We know that addition and subtraction can be done only if both the quantities have same units.
AB = 5 cm 6 mm = (5 x 10) + 6 mm = 56 mm [$\because$ 1 cm = 10 mm]
AC = 10 cm 2 mm = (10 x 10) + 2 = 102 mm
Then, BC = AC - AB
= 102 - 56 mm
= 46 mm
= 4 cm 6 mm [$\because$ 10 mm = 1 cm]