A bag contains 8 white marbles, 6 red marbles and 4 blue marbles. How many blue marbles must be added to the bag so that the probability of choosing a blue marble is 1/2?

5 marbles

Step-by-step explanation:

A bag contains

8 white marbles

6 red marbles

4 blue marbles.

Total number of marbles is :

8 + 6 + 4

= 18 marbles

Based on this current proportion

The Probability of choosing a blue marble = Number of blue marbles/ Total number of marbles

In order for the Probability of choosing a blue marble to be 1/2

The number of blue marbles has to be:

= 18 marbles × 1/2

= 9 blue marbles

From the question we have 4 blue marbles, hence:

9 blue marbles - 4 blue marbles

= 5 blue marbles

Therefore, 5 blue marbles must be added to the bag so that the probability of choosing a blue marble is 1/2.

the inequality is:

250c+180g≥950

step-by-step explanation:

let c denotes the number of days in a week   miyoko worked as a cryptographer.

and g denotes the number of days in a week she works as a geologist.

now we are given that she earns $250 for every day she works as a cryptographer,and earns $180 for every day she works as a geologist.

now miyoko's goal is to earn more than $950 this week.

hence, the inequality could be represented as:

250c+180g≥950