Please help me answer these questions with full solutions with standard score and normal curve topic in stats I will give high feedback

3. If Sarah scored 78 on her History test which had a mean of 70 and a standard deviation of 3 and she scored 84 on her Math test which had a mean of 80 and a standard deviation of 2, on which test did she score better? 4. A China-based bulb manufacturer claims that their bulb had a better performance with an average life span of 40 months with a standard deviation of3.5 months of continued usage compared with a Japan based manufacturer claimed that their bulb had an average of 37 months and a standard deviation of 2 months. Dan wants verify their claims and he found out that the China-based product lasted for 42months while a Japan-based product lasted for 40 months. Which product had better performance