L = 20 W = 1
L = 10 W = 2
L = 5 W = 4
Study this carefully. It's a good problem to know how to do. The ancients solved problems by using this method. They started with biggest number they could on the left and multiply each number on the right as they went down (in this case by 2).
Answer:
6 and 10
Step-by-step explanation:
xy=60
2(x+y)=32
x+y=16
y=16-x
Substitute y into area equation
x(16-x)=60
16x-x^2=60
x^2-16x+60=0
(x-10)(x-6)=0
x=10, 6
y=6, 10
Answer is in the photo. I can only upload it to a file hosting service. link below!
tinyurl.com/wtjfavyw
Z varies inversely as w ⇒ z*w=k
z=40 , w=0,1 ⇒40*0,1=4=k
z*20=4
z=4/20=1/5
z=0,2
40 out of 250 students speak French: 40 / 250 = 0.16
Multiply the number of students surveyed by 0.16:
30 x 0.16 = 4.8
Round up to 5 students.
Answer 5 students