Suppose you wanted to start a fire using a mirror to focus sunlight. which of the following statements is most accurate? a. it would be best to use a concave mirror, with the object to be ignited positioned at the center of curvature of the mirror. b. it would be best to use a concave mirror, with the object to be ignited positioned halfway between the mirror and its center of curvature.

The temperature in gavin's oven is a sinusoidal function of time. gavin sets his oven so that it has a maximum temperature of 280°f and a minimum temperature of 240°. once the temperature hits 280°, it takes 20 minutes before it is 280° again. gavin's cake needs to be in the oven for 30 minutes at temperatures at or above 270°. he puts the cake into the oven when it is at 260° and rising. how long will gavin need to leave the cake in the oven? (round your answer to the nearest minute.)