Ten 100 W light bulb burns on an average of 10 hours a day for one week. The weekly consumption of energy will be ____ units.
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Think of a "unit" as keeping a 1000-Watt appliance (like a small heater) running for exactly one hour. Here, your 10 bulbs combined act like that 1000-Watt appliance.
Step 1: Find how much energy a single 100 W bulb uses in one week. Running 10 hours a day for 7 days gives \( 10 \times 7 = 70 \) hours total for that one bulb.
Step 2: Convert that single bulb's weekly energy to kWh: \( \frac{100\text{ W} \times 70\text{ h}}{1000} = 7\text{ kWh} \).
Step 3: Since there are 10 identical bulbs, multiply this single-bulb weekly energy by 10 to get the total consumption: \( 7\text{ kWh} \times 10 = 70\text{ kWh} \).
\[ \boxed{70 \text{ units}} \]