https://preparationpoint.info/solved-past-papers-mcqs/ppsc-past-papers/ppsc-past-papers-2018/model-paper-65-excise-taxation-inspector-bs-16-2018-region/rashid-buys-3-books-for-rs-16-each-and-four-books-for-rs-23-each-what-will-be-the-average-price-of-books/