Answer:
z=0.77
Explanation:
If 22% of the area under the standard normal curve lies to the right of z, 78% lies to the left.
According to a one-sided z-score table:
If z-score = 0.77 the area under the curve is 77.94%
If z-score = 0.78 the area under the curve is 78.23%
Since only two decimal plates are required, there is no need to actually interpolate the values, just verify which one is closer to 78%
Since 77.94% is closer, a z-score of 0.77 represents a 22% area under the standard normal curve to the right of z.