Voy a responder en el mismo idioma en que está la pregunta.
1) Venta con ganancia
Precio de venta 60 soles.
Ganancia = 20% del costo => costo + 0,20 * costo = precio
=> costo (1 + 0,20) = precio = 60 soles
=> costo (1,20) = 60 soles => costo = 60 soles / 1,20 = 50 soles
2) Venta con pérdida del 20%
Pérdida = 20% del costo
=> costo - precio = 20% * costo => costo - 0,20*costo = precio
=> costo ( 1 - 0,20) = 60 soles => costo * 0,80 = 60 soles
=> costo = 60 soles / 0,80 = 75 soles
3) Costo total = 50 soles + 75 soles = 125 soles
4) Ganancia total = valor total de venta - costo total
Ganancia total = 2 * 60 soles + 125 soles = 120 soles - 125 soles = - 5 soles.
El signo negativo significa que al final se perdió 5 soles en la operación.
The answer is 35/10 and 6/10
It most common to round to the hundredths place, this is two spaces after the decimal.
So look two spaces right - 0.17. If the third digit (in this case 6) is higher than 5 you round the number up if its not, keep it the same.
"6" is greater than five, so round it to about (or approximately) 0.18.
we are given

Firstly, we will simplify left side
and then we can solve for k
Left side is

we can arrange like terms



now, we can use property of exponent



now, we can equate it with right side
and we get

We can see that both sides have 30 , a and b
and they are equal
so, exponent of a must also be equal

now, we can solve for k

................Answer
The answer is between B and C but... I'm kinda leaning more towards B but, you choose which one you think is right.
Hope I helped you. :)