24. The surface are of a certain plant that requires painting is 8,000 sq. ft. Two kinds of paint are available whose brands are A and B. Paint A costs P1.40 per sq. ft. but needs renewal at the end of every 4 years, while paint B costs P1.80 per sq. ft. If money is worth 12% effective, how often should paint B be renewed so that it will be as economical as Paint A? Ans. 5.58 years