Hi, i new here but im hoping someone can help me with some maths problems.

1. Solve for A, the equation A+5 over 4 + A-6 over 3= 1 over 6 ?

Mr F says: Get rid of the fractions - multiply the whole equation by 12 (the lowest common multiple of 4, 3 and 6).
2. The area of a trapezium is given by the formula A= 1 over2 h (a+b), where h is the perpendicualr distance betweeen the two parallel sides and a and b are the lenghts of the parallel sides.

i. Transpose the formula, solving for a

Mr F says: Multiply by 2. Divide by h. Subtract b.
ii. Determine the lenght of a if the area of the trapezium is 17.5cm squared, the perpendicular distance between the two parellel sides is 2.5am and the lenght b is 6cm.

Mr F says: Substitute into the above A = 17.5, h = 2.5, b = 6.
3. Andrew is paid a commision of 12.5% on all the sales he makes. If he earns $4100 in commission in one month, what were his sales for the month?

Mr F says: Solve (12.5/100) x = 4100 => x/8 = 4100 ......
4. An express train takes 5 and a hafl hours to travel between two cities. If the express train takes only 3/5 of the time an ordinary train takes, how long does it take the ordinary train to travel between the two cities?

Mr F says: Solve . I'd suggest first multiplying through by 10 (the lowest common multiple of 5 and 10).
Thanks whoever can help