The number of pollen grains, produced by each inflorescence of family Asteraceae having 10 actinomorphic flowers (given that each anther produces 20 pollen grains), are:
1000
Each flower has 5 anthers and, therefore 10 flowers will have a total of 50 anthers. Each anther produces 20 pollen grain, so total pollen grain will be 10×5×20=1000