Answer:
z = 189/44
Step-by-step explanation:
The "varies jointly" relationship can be expressed by ...
y = kxz
We can find k from the given values.
40 = k(10)(9)
40/90 = k = 4/9 . . . divide by the coefficient of k
Now we want to find z for given values of x and y. That can be found from ...
y = (4/9)xz
9y/(4x) = z . . . . . multiply by 9/(4x)
Filling in the new numbers, we have ...
z = 9·105/(4·55)
z = 4 13/44 = 189/44 ≈ 4.2954...(repeating 54)
Let's first find out their factors.
90's factors are :

190's factors are :

The common factors of 90 and 190 are :
1,2,5 and 10.
The greatest one among these is, 10. So the greatest factor of 90 and 190 is 10.
Answer: 6
<u>Step-by-step explanation:</u>
Let x represent the number of plates bought for $6
Let y represent the Total number of plates bought = x + 1
<em>Remember that Mrs. Lim bought another plate for $18</em>
Total cost ÷ Total plates = Average Cost

6x + 18 = 8(x + 1)
6x + 18 = 8x + 8
18 = 2x + 8
10 = 2x
5 = x
y = x + 1
= 5 + 1
= 6