<prompt> Weight of an infant doubles by what age?6 months1 year2 years3 years  <response>: Ans. is a i.e., 6 months Weight of an infant doubles by 5 months and quadruples by 2 years of age.AgeWeightBirth3kg5 months6kg 2 x birth weight1 years9kg 3 x birth weight2 years12kg 4 x birth weight3 years15kg 5 x birth weight5 years18kg 6 x birth weight7 years21kg 7 x birth weight10 years30kg 10 x birth weight 