before
c muffins: 40%
r and b muffins: 60%

r muffins = 80% x 60% = 0.8x0.6
= 0.48 = 48% (of total)

b muffins = 60%-48% = 12% (of total)


sale
c muffins: 40%x20% = 8% (of total)
r muffins = 48% x 25% = 12% (of total)
b muffins = 1/3 x 12% = 4% (of total)


(a)
percentage of muffins sold
= 8+12+4 = 24% (of total)


(b)
percentage of muffins left
= 100 - 24% = 76% (of total)

76% = 114
100% = 150 (=> total no.)

c muffins left = 40%x80% (or 40-8)
= 32% (of total)

b muffins left = 2/3 x 12%
= 8% (of total)

32-8 = 24%

24% x 150 = 36

36 more c muffins more than b muffins left.


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