Un químico agrega cierta cantidad de una solución de 86% de alcohol a 11 litros de otra solución al 71% de alcohol y obtiene una solución al 77% de alcohol encuentre la cantidad de litros de la primera solución que se agregaron a la segunda

Step-by-step explanation:

Sea x la cantidad de litros de la mezcla al 86%

x× 86% + 11 × 71% = (x + 11) × 77%

0.86x + 7.81 = 0.77x + 8.47

x + y = 90 5x – 10y = 90 90 – 10y = 5x 90 + 10y = 5x

step-by-step explanation:

last month maria hiked the 5-mile mountain trail a number of times and she hiked the 10-mile canal trail several times. let x represent the number of times she hiked the 5-mile trail, and let y represent the number of times she hiked the 10-mile trail. if she hiked a total of 90 miles, which equation can be used to find the number of times maria hiked each trail? x + y = 90 5x – 10y = 90 90 – 10y = 5x 90 + 10y = 5x

step-by-step explanation :

we know that

the measurement of the outer angle is the semi-difference of the arcs which comprises

in this problem

m< xzy is the outer angle

substitute the values

the measure of angle xoy is equal to

> by central angle

substitute the value