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Math problem help!!!!!!!!?

1)There are approximately 250 million passenger vehicles registered in the United States. Assume that the battery in the average vehicle stores 440 watt-hours (Wh) of energy. Estimate (in gigawatt-hours) the total energy stored in US passenger vehicles 2) A hand-held video player displays 320x240 picture elements in each frame of the video. Each pixel requires 2 bytes of memory. Videos are displayed at a rate of 30 frames per second. How many minute of video will fit in a 30 gigabyte memory?

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1. Hi, 1) Since there are 440watt-hours for each passenger vehicle, while we have 250 million passenger vehicles, we can get the total energy stored by multiplying both figure, so that the value is: 440 * 250,000,000 Watt-hours = 110,000,000,000 Watt - hours However, we want the value to be in Gigawatt-hours. 1 Gigawatt = 1,000,000,000 watt Therefore, the answer to this is = 110,000,000,000 Watt - hours = 110 GigaWatt - hours ====================== Answer = 110 GigaWatt - hours ====================== 2. Wow, this will be a bit long to explain, but here goes :) Just for your information, pixel stands for 'picture elements' From the data, we can obtain the total amount of pixels in each frame of the video, that is: 320 x 240 = 134,400 pixels Now, since each pixel requires 2 bytes of memory, and we have 134,400 pixels, therefore the amount of memory for a frame of video is 134,400 * 2 = 268,800 bytememory / frame. Thus, how many frames will be displayed in a 30gigabyte memory? We can just divide this, so that: 30,000,000,000 / 268,800 = 111607.143 frames = 111607 frames -- rounding down Next, we have to find the time to display 111,607 frames. We have the information that "Videos are displayed at a rate of 30 frames per second". Therefore, the total amount of seconds to display 111,607 frames is: 111607/30 = 3720.233 seconds = 3720 seconds (rounding down) But we want the answer in minute. Therefore, 3720 seconds = 3720/60 minutes = 62 minutes. =================== Answer: = 62 minutes =================== Hope this helps Kind regard, Ryonn
2. im hope im correct 1.(11 gigawatts) 2.(3.616)gigabytes
3. 1. 250 x 10 ^6 vehicles x 440 watt-hr / vehicle x 10^-6 gigawatt-hr / watt hour you can do the calculation from here 2. 30 GB/ [(320 x 240 pixels / frame x 2B/pixel x 10^-6GB/B x 30 frames/sec x 60 sec/min)] remember to treat units as algebra and work from there Understand what I did - and all other problems will fall into place