A body cream A weighing 100grams contains 5% of sulphur ointment

Question

A body cream A weighing 100grams contains 5% of sulphur ointment and another body cream B of thesame weight as cream A contains 80% of sulphur ointment. what quantities of cream A and B will be mixed together to make cream C weighing 30gram and containing 7% sulphur ointment. show workings

Answer 1

A + B = 30 gm

B = 30 - A

 

0.05A + .8(30 - A) = 0.7(30)           Multiply all by 100 to clear decimal

5A + 80(30 - A) = 70(30)

5A + 2400 - 80A = 2100

-75A = -300

A = 4

 

Mix 4 gm of A and 36 gm of B.