im really sorry for asking so many question and you dont need to answer them but if any one can help me with question it will be very appriciated : "a dealer paid for 2 different items 90$ (not the real given money). he sold the items and he earned 40% more on the whole deal ( he earned more then spent). on the first product he earned 5% and on the second one he earned 50%. how much did he paid for each product".
Let the price he paid for the first item be f, and the price he paid for the second item be s.
We are told that: f + s = 90 ...(1)
What he got for the first item is: 1.05*f and on the second he got 1.5*s. The sum of these two equals what he got in total, which we are told is 1.4*90, so: 1.05*f + 1.5*s = 1.4*90 ...(2)
Rearrange eqn (1) to get: f = 90 - s. Put this in eqn (2) to get 1.05*(90 - s) + 1.5*s = 1.4*90 or
1.05*90-1.05*s+1.5*s = 1.4*90
See if you can take it from here. Having found s, you can substitute this back into eqn (1) to find f.
Let the price he paid for the first item be f, and the price he paid for the second item be s.
We are told that: f + s = 90 ...(1)
What he got for the first item is: 1.05*f and on the second he got 1.5*s. The sum of these two equals what he got in total, which we are told is 1.4*90, so: 1.05*f + 1.5*s = 1.4*90 ...(2)
Rearrange eqn (1) to get: f = 90 - s. Put this in eqn (2) to get 1.05*(90 - s) + 1.5*s = 1.4*90 or
1.05*90-1.05*s+1.5*s = 1.4*90
See if you can take it from here. Having found s, you can substitute this back into eqn (1) to find f.