The answer: 46 and 2/6cm
Step-by-step explanation:
First, turn the mixed numbers into improper fractions:
12 and 1/2 is 25/2
25/2 + 25/2 = 50/2
10 and 2/3 is 32/3
32/3 + 32/3 = 64/3
Next, change the fractions so there is a common denominator:
50/2 = 150/6
64/3 = 128/6
Add the two fractions together:
150/6 + 128/6 = 278/6
Turn this back into a mixed number:
278/6 = 46 and 2/6