Question

lena finished her assignment in 1/2 hours. then she completed her other assignment in 1/5 hours. what was the total time lena spent doing these assignments.

Answer 1

7/10 hours

Explanation:

her first assignment took 1/2 hour

her second assignment took 1/5 hour

so in total she took 1/2 + 1/5

we need to find a common denominator

the lcm(2,5)=10

so multiply 1/2 by 5/5 to obtain 5/10

multiply 1/5 by 2/2 to obtain 2/10

5/10 + 2/10 = 7/10