This problem is simply asking us to add the weights which are presented as fractions. You can easily get the answer if you input them directly in a calculator. But I think the challenge here is to manually add fractions.
Let's add the two 1/4 lb weights because it is easier for they have a common denominator. Just simply add the numerators.
1/4 + 1/4 = 2/4
Then, add with this the fraction part of 2 1/5.
2/4 + 1/5 = ? The least common denominator is 4*5 = 20. Then divide 20 with each denominator and multiply to their respective numerator.
2/4 + 1/5 = [(20/4 * 2) + (20/5 *1)]/20 = 14/20
14/20 is simplified to 7/10. Then add the whole number 2. <em>Therefore, the sum of all weights is 2 7/10 pounds.</em>
