Age-related discrimination and stereotyping remains "firmly embedded" in British society, according to a new government report.
The survey, conducted by the Department for Work and Pensions, concluded ageism is a serious problem in the UK and needs to be tackled due to the rapidly ageing population.
Researchers compared attitudes between two key groups - people in their 20s and people over 70 - using data from a 2010/11 Office for National Statistics survey of almost 2,200 people.
During questioning, respondents were asked how acceptable or unacceptable they would find a suitably qualified 30-year-old or 70-year-old boss. While most respondents were accepting of either, three times as many (15% and 5% respectively) said having a boss in their 70s would be "unacceptable" compared with having a boss 40 years younger.
Meanwhile, one in three people said they had experienced age-related prejudice in the last year, with the under-25s at least twice as likely to have experienced discrimination than other age groups.
The average person said old age started at 59 and youth ended at 41, but this varied by as much as 20 years in relation to the age and sex of the respondent, with women and older people saying youth ended later in life.
Analysts found people over the age of 70 were perceived in a more positive light than those in their 20s, with septuagenarians viewed as more friendly, having higher moral standards and as being more competent.
The report, named Attitudes to Age in Britain, also discovered that people in their 40s were viewed as having the highest status of all age groups, with people aged over 70 considered to have a higher status than those in their 20s.
Researchers concluded that ageism is a problem for young and old alike and that attitudes needed to change.
It said: "Overall, age-related discrimination and stereotypes are firmly embedded in British society and their scope is wide ranging. Tackling age discrimination requires strategies that address individual's assumptions and attitudes about age - about themselves and others - to ensure that they do not impinge on judgments about a person's ability, health or rights to services."