The sum of the percentages of milk and dark chocolate needs to equal 100%.
Since dark chocolate is 25%, then milk chocolate must be 75%
Now we can set up a proportion:
75% = 3 lbs
25% = X lbs
Dark chocolate = (3 x 25%) / (75% x X) = 1 lb
-- Look at the two numbers.
-- Say to yourself: "Self ! 3.9 is close to 4, and 5.3 is close to 5.
So the product is going to be close to (4 x 5) = 20."
-- Then do the real multiplication.
-- On your paper or your calculator, you see the digits 2 0 6 7 .
-- From your estimate (20), you know that it can't possibly be
2.067 or 206.7 or 2,067. It must be 20.67 .
The answer is 193 baskets because you have to multiply the amounts of baskets and then add the left overs.
12x15=180
180+13=193
Hope this helps!;)