Xavier, Yaozhou and Zara had some beads. Xavier and Yauzhou had a total of 438 beads. Xavier and Zara had a total of 04 beads. Yaozhou had 3 times as many beads as Zara. How many beads did Xavier have?

Xavier has 136 beads, Yaozhou has 204 beads and Zara has 68 beads.

Step-by-step explanation:

Let the number of beads that Xavier has be x.

Let the number of beads that Yaozhou has be y.

Let the number of beads that Zara has be z.

The total number of beads they have altogether is 438. This means that:

x + y + z = 438 (1)

Xavier and Zara have a total of 204 beads. This means that:

x + z = 204

=> x = 204 - z (2)

Yaozhou has 3 times as many beads as Zara. This means that:

y = 3z (3)

Put (2) and (3) in (1):

204 - z + 3z + z = 408

3z = 408 - 204 = 204

z = 204/3 = 68

From (2):

x = 204 - 68 = 136

From (3):

y = 3 * 68 = 204

Therefore, Xavier has 136 beads, Yaozhou has 204 beads and Zara has 68 beads.

d. 24+-0.114

step-by-step explanation:

the question requires us to calculate the approximate 95% confidence interval for the mean number of ounces of ketchup per bottle in the sample given the following statistics;

sample mean = 24

standard deviation, σ = 0.4

sample size , n = 49

the confidence interval for a population mean is calculated using the formula;

sample mean ± z-score*(σ/sqrt(n))

the z-score associated with a 95% confidence interval, from the standard normal tables, is;

1.96

substituting these values into the formula;

24 ± 1.96*(0.4/7)

= 24 ± 0.112

from the alternatives given, choice d is closest to the above expression;