i dont understand

There are 2 different sales of T-shirt: 1. Sales of 60% of the T-shirt at $5 each; 2. 3/4 of the remaining 40% at a discount of 40%. For the first sales, 60% = 60/100 = 6/10. For the second sales, 3/4 of the remaining 40% = 3/4 x 40/100 = 3/10. Hence, it's similar to a model drawing of 10 units. 6 units are sold at $5 and 3 units are sold at $2 (discount of 40%). Let x be the total number of T-shirt that Mdm Savithi bought. Hence, number of T-shirt which are sold at $5 = 6x/10 and the number of T-shirt sold at $2 = 3x/10. Solve the equation to get x