4. In the store "Everything for School," chalk is sold in packages of three grades: regular, unusual, and superior. Initially, the ratio of the quantities by grade was 2:3:6. After a certain number of packages of regular and unusual chalk, totaling no more than 100 packages, were delivered to the store, and 40% of the superior chalk packages were sold, the ratio changed to 5:7:4. How many packages of chalk were sold in total in the store?

(7 points)

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# Answer: 24 packs.

Solution: a similar solution to this problem is present in Variant 1 under the same number.