Answer :
Dean’s oven takes 1 minute to warm up for every [tex]$20^\circ\text{C}$[/tex] increase in temperature. This means that for any given target temperature [tex]$T$[/tex], the time required is given by
[tex]$$
\text{Time} = \frac{T}{20}.
$$[/tex]
Let’s calculate the warm-up time for each temperature:
1. For [tex]$T = 180^\circ\text{C}$[/tex]:
[tex]$$
\text{Time} = \frac{180}{20} = 9 \text{ minutes}.
$$[/tex]
2. For [tex]$T = 220^\circ\text{C}$[/tex]:
[tex]$$
\text{Time} = \frac{220}{20} = 11 \text{ minutes}.
$$[/tex]
3. For [tex]$T = 200^\circ\text{C}$[/tex]:
[tex]$$
\text{Time} = \frac{200}{20} = 10 \text{ minutes}.
$$[/tex]
4. For [tex]$T = 160^\circ\text{C}$[/tex]:
[tex]$$
\text{Time} = \frac{160}{20} = 8 \text{ minutes}.
$$[/tex]
Thus, the times required for each temperature are:
- (a) [tex]$180^\circ\text{C}$[/tex]: [tex]$9$[/tex] minutes
- (b) [tex]$220^\circ\text{C}$[/tex]: [tex]$11$[/tex] minutes
- (c) [tex]$200^\circ\text{C}$[/tex]: [tex]$10$[/tex] minutes
- (d) [tex]$160^\circ\text{C}$[/tex]: [tex]$8$[/tex] minutes
[tex]$$
\text{Time} = \frac{T}{20}.
$$[/tex]
Let’s calculate the warm-up time for each temperature:
1. For [tex]$T = 180^\circ\text{C}$[/tex]:
[tex]$$
\text{Time} = \frac{180}{20} = 9 \text{ minutes}.
$$[/tex]
2. For [tex]$T = 220^\circ\text{C}$[/tex]:
[tex]$$
\text{Time} = \frac{220}{20} = 11 \text{ minutes}.
$$[/tex]
3. For [tex]$T = 200^\circ\text{C}$[/tex]:
[tex]$$
\text{Time} = \frac{200}{20} = 10 \text{ minutes}.
$$[/tex]
4. For [tex]$T = 160^\circ\text{C}$[/tex]:
[tex]$$
\text{Time} = \frac{160}{20} = 8 \text{ minutes}.
$$[/tex]
Thus, the times required for each temperature are:
- (a) [tex]$180^\circ\text{C}$[/tex]: [tex]$9$[/tex] minutes
- (b) [tex]$220^\circ\text{C}$[/tex]: [tex]$11$[/tex] minutes
- (c) [tex]$200^\circ\text{C}$[/tex]: [tex]$10$[/tex] minutes
- (d) [tex]$160^\circ\text{C}$[/tex]: [tex]$8$[/tex] minutes