A security dealer recommends two types of investments A and B to his client Investment A returns 6% and B 8%.The client has almost Rs 100000 to invest. The client wants the total annual returns to be at least Rs 7000 and at least 2/5th of the amount to be invested in investment B. The security dealer gets 5% of the income from investment A and 4% of the income from investment B. Construct the mathematical for the problem to maximize the total fee of the security dealer.