2*3 = 6 teaspoons per day per child
6*5 = 30 teaspoons
30*3 = 90 teaspoons
You need 90 teaspoons
1 teaspoon = 4.9289 mL
90*4.9289 = 443.6010 mL
443.6010 / 150 = 2.9573 bottles
You need at least 3 bottles
You just have to count the boxes between them which is 6