Question

An adult eats food whose nutritional energy totals approximately 2400 Cal per day. The adult burns 2100 Cal per day. How much excess nutritional energy, in kilojoules, does the adult consume per day? Express your answer using one significant figure.

Answer 1

Notice the way Cal is written.It is written with a capital C.Sometimes,error occurs when capital C is replaced with small c.Here,I am assuming that the Cal is with a capital C.

So,

Energy obtained = 2400 Cal

Energy burnt = 2100 Cal

Excess nutritional energy = Energy obtained - Energy burnt

Excess nutritional energy,

= 2400 Cal per day - 2100 Cal per day

= 300 Cal per day

Also 1 Cal = 4184 J

So 300 Cal per day = 300 × 4184 = 1255200 J = 1255.2 kJ per day

Now since the final answer is asked in 1 significant figure , so 1255.2 kJ per day will become 1000 kJ per day

So the final answer will be 1000 kJ per day