Direct, Joint and Inverse Variation

• direct variation
• inverse variation
• neither direct nor inverse variation

• direct variation
• inverse variation
• neither direct nor inverse variation

• direct variation
• inverse variation
• neither direct nor inverse variation

The equation    
w = 10chs  represents:

• direct variation
• inverse variation
• joint variation
• none of these

The equation 
xy =  25  represents:

• direct variation
• inverse variation
• joint variation
• none of these

• direct variation
• inverse variation
• joint variation
• none of these

• direct variation
• inverse variation
• joint variation
• none of these

• direct variation
• inverse variation
• joint variation
• none of these

• direct variation
• inverse variation
• joint variation
• none of these

Suppose y varies directly as x.
If  y = 22.5 when x = 15, find y when x = 20.

• 1.5
• 337.5
• 30
• 16.875