Question

the expenses of a tea party are partly constant and partly vary directly with the number of guest.when there are 60 guest,the expenses are $2100.when there are 150 guest , the expenses are $4800.find the expenses when there are 200 guest​

Answer 1

$6300

Explanation:

Using the equation of y=mx+c where c is constant, m is gradient then the two situations can be written as

2100=60x+c Equation 1

4800=150x+c Equation 2

Subtracting the terms of equation 1 from 2

(150-60)x=$4800-$2100

90x=$2700

x=$30

Substituting the value x into equation 1

60($30)+c=$2100

c=$2100-$1800=$300

c=$300

For 200 guests

y=200($30)+$300

y=$6000+$300=$6300