Question

MONICA PAID SALES TAX OF 1.50 WHEN SHE BOUGHT A NEW BIKE HELMET . IF THE SALES TAX RATE WAS 5% HOW MUCH DID THE STORE CHARGE FOR THE HEMELT BEFORE TAX

Answer 1

Let h be the price of the helmet (not hemelt).  Then 0.05h= $1.50.
To determine the price of the helmet, divide both sides of this equation by 0.05:

h = $30

The helmet is $30 before sales tax is applied, and $31.50 with tax.